• Journal of the Korean Society for Precision Engineering
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• v.21 no.2
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• pp.52-59
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• 2004

In this paper, the automatic system generation algorithm based on the element combination algorithm discussed in the first part of this paper for designing an arbitrary type of the automatic transmissions is proposed. The powertrain design software using these algorithms is developed. This automotive powertrain design software with user-friendly graphic user interface has two main modules. The first module, the automatic power flow generation module, is already discussed in the previous paper. The second module dealing with the automatic system generation algorithm is discussed in this paper. The power-flow simulation software fur the arbitrary type of powertrain is then developed. The simulation and experimental results of the vehicle equipped with two planetary gear type automatic transmission are compared to validate the proposed algorithms and developed software. The simulation results demonstrate the good agreement with the experimental results.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.6
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• pp.830-836
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• 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.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.877-880
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• 2009

수문의 개폐는 모터에 의한 회전이 권양기에서 감속 되고 증폭된 회전력이 랙에 의하여 직선 운동으로 바뀌어 회전 방향에 따라 상하로 움직여 열리고 닫히게 된다. 권양기는 상부 모터, 감속기, 메인 감속 장치, 동력 차단장치, 좌측 동력변환장치, 우측 동력 변환장치로 구성된다. 본 논문에서는 핀잭식 권양기의 최적 설계를 위하여 보조기어와 메인기어 트레인의 구조 해석, 진동해석 및 설계와 하중에 버틸 수 있는 상부구조물 몸체의 최적 설계를 통하여 설계변수를 확립한다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.5
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• pp.57-65
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• 2016

The power flow of an 8-speed automatic transmission was analyzed using a lever analogy for the manufacturing of planetary gears. From the analysis, we found that the engine power was split between the first and second double-pinion planetary gears (DPPG1 and DPPG2), and was then passed to the DPPG3 for the fourth speed. For the fifth speed, the engine power was split between the DPPG1 and DPPG3. For the speeds 6-8, the engine power was passed only to SPPG2, while the seventh speed contained the power circulation.

• Tribology and Lubricants
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• v.38 no.1
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• pp.22-26
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• 2022

A 1.7-ton grade small excavator is a construction equipment that can perform various functions in limited spaces where heavy equipment cannot enter easily. Owing to the recent acceleration of urbanization, it has been used increasingly in drainage and gas pipes, as well as for road repair works in urban areas. The power train of a traveling reducer for a 1.7-ton grade small excavator utilizes a complex planetary gear system. Complex planetary gears are vital to the power train of a traveling reducer as it mitigates the fatigue strength problem. In the present study, the specifications of a complex planetary gear train are calculated; furthermore, the gear bending and compressive stresses of the complex planetary gears are analyzed to achieve an optimal design of the latter in terms of cost and reliability. In this study, the actual gear bending and compressive stresses of a planetary gear system are analyzed using a self-developed gear design program based on the Lewes and Hertz equation. Subsequently, the calculated specifications of the complex planetary gears are verified by evaluating the results with the data of allowable bending and compressive stress based on curves of stress vs. number of cycles of the gears.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.2
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• pp.43-51
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• 2004

In this paper, the element combination algorithm for designing an arbitrary type of the automatic transmissions is proposed. The powertrain simulation software using this algorithm is then developed. The deliveries of the angular velocities and torques are only considered for the motion characteristics of the automatic transmissions. The effects of the vibration and noise are not considered. The automatic transmission is defined by the basic elements, i.e., planetary gear set, clutch, brake, shaft, general gear, and inertia. The transmission system is defined by the combination of these elements. The element combination matrices automatically generate the equations of motion for each shift. The self error-correcting algorithm is also developed to verify the element combination algorithm. This automotive powertrain simulation/design software with user-friendly graphic user interface has two main modules. The first module, the automatic powerflow generation module, mainly consists of the automatic powerflow and component generation algorithms. This paper covers the theory and application for the first module. The second module deals with the automatic system generation algorithm and will be discussed in the second paper.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.5
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• pp.48-56
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• 2016

In this paper, we analyze the power flow of an eight-speed automatic transmission by using a lever analogy for the manufacturing of planetary gears. The results indicate that the engine power is passed down to the carrier and ring gear in the first double pinion planetary gear (DPPG1), and to the sun gear, carrier, and ring gear in DPPG3 for the first speed. Although the power flow is similar in the second speed, the power circulation occurs in the second single pinion planetary gear (SPPG2). For the third speed, the engine power is passed from the carrier to the ring gear in DPPG, at which point the power is split between the sun gears of SPPG2 and DPPG3.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.4
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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.

• Journal of Drive and Control
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• v.14 no.1
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• pp.1-7
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• 2017

The power train of a concrete truck mixer reducer includes differential planetary gears to get a large reduction ratio for operating the mixer drum in a compact structure. These differential planetary gears are a very important part of the mixer reducer where strength problems are the main concern. Gear bending stress, gear compressive stress and scoring failure are the main concerns. Many failures in differential planetary gears are due to the insufficient gear strength and resonance problems caused by major excitation forces such as gear mating failure in the transmission. In the present study, where the excitation frequencies are the gear tooth passing frequencies of the mating gears, a Campbell diagram is used to calculate differential planetary gear critical speeds. Mode shapes and natural frequencies of the differential planetary gears are calculated by CATIA V5. These are used to predict gear resonance failures by comparing the working speed range with the critical speeds due to the gear transmission errors of the differential planetary gears.

• Journal of Drive and Control
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• v.14 no.4
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• pp.71-78
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• 2017

The power train of hydro-mechanical continuously variable transmission (HMCVT) for 8-ton class forklift includes hydro-static units, hydraulic multi-wet disc brake & clutches and complex helical & planetary gears. The helical & planetary gears are key components of HMCVT's power train wherein strength problems are the main concerns including gear bending stress, gear compressive stress, and scoring failure. Many failures in power train gears of HMCVT are due to the insufficient gear strength and resonance problems caused by major excitation forces, such as gear transmission error of mating gear fair in the transmission. In this study, wherein excitation frequencies are the gear tooth passing frequencies of the mating gears, a Campbell diagram is used to calculate the power train gears' critical speeds. Mode shapes and natural frequencies of the power train gears are calculated by CATIA V5. These are used to predict resonance failures by comparing the actual working speed range with the critical speeds due to the gear transmission errors of HMCVT's power train gears.