• 한국기계가공학회지
• /
• 제14권6호
• /
• pp.14-20
• /
• 2015

A high-speed reduction transfer case is usually employed by an excavator, wheel loader, or bulldozer. When powerful torque is required in the case of climbing steep roads or towing heavy equipment, the high-speed reduction mode of the gearbox is used. Generally, a transfer case using a spur gear type with a speed reduction system has a speed reduction ratio of 1 to 1 or 2 to 1. However, the structure of a transfer case achieved at a high speed of 1 to 1 and a low speed of 4.5 or under 5.5 to 1 with the speed reduction by use of a planetary gear type with a speed reduction system was proposed in this study. By employing a planetary gear type with a speed reduction system, the compact structure of the transfer case was achieved, and the impact or the partial defect of gear teeth was eliminated.

• 한국가스학회지
• /
• 제26권2호
• /
• pp.9-13
• /
• 2022

벨트나 체인을 이용한 감속기는 간단한 장치이긴 하지만 공간을 많이 차지하여 공간상의 제약이 있기 때문에 전동휠체어 구동부에는 부적합하다. 하지만 유성기어형태의 감속기는 동일 축에서 감속이 이루어지기 때문에 부피를 작게 할 수 있어 공간의 제약이 벨트나 체인형태의 감속기보다 덜하다. 따라서 본 연구에서는 수·전동전환이 가능한 휠체어의 구동부에 대한 연구를 통하여 유성기어형태를 이용한 감속기로 큰 추진력을 얻을 수 있는 구동부를 개발하였다. 그에 따라 감속기에 적용되는 유성기어의 치형을 Kisssoft 프로그램을 이용하여 설계를 진행하였다. 또한 기존 휠체어 바퀴에 적용 가능하도록 구동부의 설계를 진행하였고, 구동부의 수·전동 전환원리 및 작동원리에 대한 메커니즘의 최적화를 진행하였다. 연구내용을 토대로 하나의 선기어와 2개의 유성기어, 하나의 링기어를 갖는 유성기어 형태의 휠체어 감속기 구동부의 최종 설계 및 제작을 진행하였다.

• Journal of Mechanical Science and Technology
• /
• 제18권4호
• /
• pp.606-621
• /
• 2004

A dynamic analysis using a hybrid finite element method was performed to characterize the effects of a number of manufacturing errors on bearing forces and critical tooth stress in the elements of a planetary gear system. Some tolerance control guidelines for managing bearing forces and critical stress are deduced from the results. The carrier indexing error for the planet assembly and planet runout error are the most critical factors in reducing the planet bearing force and maximizing load sharing, as well as in reducing the critical stress.

• 한국생산제조학회지
• /
• 제20권6호
• /
• pp.830-836
• /
• 2011

Most of pitch/yaw reducers consist of several planetary geartrains. Planetary geartrains make gearboxes to be small and light, low noise and good efficiency. Most important thing in the planetary geartrain is load distribution on the gear tooth flank. In this study, the effect of output shaft bearings on the load distribution of gear tooth flank has been investigated. The commercial software was employed to compare the load distribution of two models depending on the bearing type. The spherical roller bearing(SRB) and the cylindrical roller bearing(CRB) were used as output shaft bearings in the $1^{st}$ model, and two taper roller bearings(TRB) were used in the $2^{nd}$ model. As a result, it was found that the $2^{nd}$ model. showed better performances on the load distribution of gear tooth flank, this results stated that the output shaft bearing system could be important consideration when designing reducers for wind turbine systems.

• International Journal of Automotive Technology
• /
• 제8권6호
• /
• pp.771-780
• /
• 2007

In recent studies, various types of multi mode electric variable transmissions of hybrid electric vehicles have been proposed. Multi mode electric variable transmission consists of two or more different types of planetary gear hybrid powertrain system(PGHP), which can change its power flow type by means of clutches for improving transmission efficiencies. Generally, the power flows can be classified into three different types such as input split, output split and compound split. In this study, we analyzed power transmission characteristics of the possible six input split systems, and found the suitable system for single or multi mode hybrid powertrain. The input split system used in PRIUS is identified as a best system for single mode, and moreover we identified some suitable systems for dual mode.

• Journal of Mechanical Science and Technology
• /
• 제18권11호
• /
• pp.1978-1988
• /
• 2004

Hybrid finite element analysis was used to analyze the influence of bearing stiffness on the static properties of a planetary gear system with manufacturing errors. The effects of changes in stiffness were similar for most of the manufacturing errors. State variables were most affected by the stiffness of the planet ,bearings. Floating either the sun or carrier helps to equal load sharing and minimizes the critical tooth stress. The effects of a floating sun and carrier are similar, but it is not recommended that both float, because this can induce greater critical tooth stress. Planet bearing stiffness should be optimized. Both load sharing and critical tooth stress should be considered to determine optimal bearing stiffness.

• 한국기계가공학회지
• /
• 제16권5호
• /
• pp.1-6
• /
• 2017

Gear tooth micro-geometry modifications include the intentional removal of material from the gear teeth flanks, so that the shape is no longer a perfect involute. If the gear shapes are perfect, then the gear tooth meshing is better, therefore the gears will transmit input torque in a more efficient manner without the generation of high frequency engine fluctuation noise. In this paper, we study tooth micro-geometry optimization of rear gear set in 2 speed planetary gear reducers. Analysis revealed problems which are need of modification. Based on the results, tooth micro-geometry was used to deal with load distributions on the rear gear set.

• 대한기계학회논문집A
• /
• 제38권2호
• /
• pp.185-192
• /
• 2014

유성기어의 설계는 모듈 등의 이산변수, 잇수 등의 정수 변수, 치폭, 종횡비 등의 연속 변수가 혼재된 복잡한 문제로 이를 해결하기 위해서는 최적 설계 기법이 적용되어야 한다. 본 연구에서는 유전 알고리즘(Genetic algorithm)을 이용한 최적 설계를 유성기어 설계에 적용하였다. 유성기어 설계시 기본이 되는 기어 잇수, 모듈, 압력각, 치폭 등과 같은 매크로 지오메트리(Macro-geometry)를 이용하여 이뿌리/치면 강도에 대한 강도 평가를 수행하였으며, 상용 프로그램과의 비교를 통해 검증하였다. 유전 알고리즘을 이용하여 기어의 체적을 최소화하기 위한 최적 설계를 수행하였으며, 이를 통하여 설계자는 초기 설계시 시행착오를 줄여 설계 시간을 단축시킬 수 있었다.

• International Journal of Precision Engineering and Manufacturing
• /
• 제1권1호
• /
• pp.62-70
• /
• 2000

The design of gear train is a kind of mixed problems which have to determine various types of design variables; i,e., continuous, discrete, and integer variables. Therefore, the most common practice of optimum design using the derivative of objective function has difficulty in solving those kinds of problems and the optimum solution also depends on initial guess because there are many sophisticated constrains. In this study, the Genetic Algorithm is introduced for the optimum design of gear trains to solve such problems and we propose a genetic algorithm based gear design system. This system is applied for the geometrical volume(size) minimization problem of the two-stage gear train and the simple planetary gear train to show that genetic algorithm is better than the conventional algorithm solving the problems that have continuous, discrete, and integer variables. In this system, each design factor such as strength, durability, interference, contact ratio, etc. is considered on the basis of AGMA standards to satisfy the required design specification and the performance with minimizing the geometrical volume(size) of gear trains

• Journal of Advanced Marine Engineering and Technology
• /
• 제38권3호
• /
• pp.253-261
• /
• 2014

본 연구에서는 스퍼 유성기어시스템 2단, 헬리컬기어 시스템 1단으로 구성되어 있고, 메인 축과 증속기가 플랜지 결합되어 있는 동력분기식 2.5MW 풍력발전기에 대해 진동해석을 수행하였다. 유성기어시스템, 헬리컬기어시스템, 메인 축 등은 MASTA 상용프로그램으로 모델링하고, 기어박스 케이스, 토크암, 유성캐리어, 플랜지 등은 유한요소법으로 모델링하였으며, 부분구조합성법으로 조합하여 진동해석을 수행하였다. 2.5MW 동력분기식 풍력발전기 기어트레인의 고유진동 특성 해석을 수행하였고, 블레이드 풍하중에 의한 가진, 질량불평형, 축 어긋남 등에 발생하는 가진원에 대해 위험속도 분석을 하였다.