• 제목/요약/키워드: SPEED REDUCTION

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대형 산업 차량에 적용되는 유성기어형 고감속 중간변속기 구현에 관한 연구 (A Study on the Embodiment of a Transfer Case with High-Speed Reduction of the Planetary Gear Type Applied to Big Industrial Vehicles)

  • 이원규;박세명
    • 한국기계가공학회지
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    • 제14권6호
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    • pp.14-20
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    • 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.

고속철도차량 감속구동장치 진동특성 분석 (Analysis on the Vibration Characteristics of Reduction Gear Units for High-speed Trains)

  • 문경호;이동형;김재철;지해영
    • 한국정밀공학회지
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    • 제30권7호
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    • pp.694-701
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    • 2013
  • The gear-reduction units of Korean high-speed trains consist of a motor reduction unit, an axle gear box reduction unit, and a tripod joint shaft. A reduction gear unit is a gearbox used to reduce the rotational speed of the input shaft to a slower rotational speed on the output shaft. This reduction in output speed helps to increase torque. Defective reduction gear units in high-speed trains are caused by damage to the gear or by gear fatigue. To diagnose potential problems, it is important to know the vibration characteristics of the reduction gear units. In this study, we analyzed the vibration characteristics of reduction gears under various conditions. The test setup included a full-scale test rig to evaluate reduction gear under both normal and extreme operating conditions.

실측자료를 통한 구간단속카메라의 소음저감효과 분석 (Effect of Noise Reduction by Installation of a Point to Point Speed Camera)

  • 손진희;전형준;정태량;박영민;김득성
    • 한국소음진동공학회논문집
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    • 제27권1호
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    • pp.57-64
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    • 2017
  • This study was reviewed the noise reduction effects with installation of 'point to point speed camera' for controlling the speed of the car. The multiple regression analysis was performed to know how the relationship between the noise level and these parameters, such as measured traffic volume and rate of heavy vehicle and weighted average speed was changed with and without the 'point to point speed camera'. In the analysis results shows that the less traffic volume, the more noise reduction effect has been increased and the more traffic volume, the more noise reduction effect has been reduced. And noise reduction effects by the 'point to point speed camera' was different from each measured point. The cause of the difference was determined that inadequate 'point to point speed camera' position to see the effect of noise reduction. It is determined to require a more study to improve the noise reduction effects of the 'point to point speed camera' such as the camera position adjustment.

고속철도차량 감속기 결함진단을 위한 진동 파라미터 분석 (Analysis of Vibration Parameters for the Fault Diagnosis of Reduction Unit for High-speed Train)

  • 김재철;지해영;이강호;문경호;서정원
    • 한국정밀공학회지
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    • 제30권7호
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    • pp.679-686
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    • 2013
  • The reduction unit is one of the most important components in railway cars, due to the transmission of torque from the motor to the wheels. Faulty reduction gears in high-speed trains result from excessive wear on the gear or damage to the gear. These types of gear defects have a significant effect on high-speed rail operation and safety; thus, a diagnosis system for the reduction unit is needed. Vibration diagnosis technology is one of the most effective diagnostics. In this paper, the vibration parameters of a reduction unit were evaluated during a driving-gear test and a full-vehicle test, using kurtosis and the crest factor. These tests were performed under normal operating conditions; a specimen tester was used to diagnose problems in defective gears.

한국형 고속전철용 감속구동장치 시운전 시험 및 평가 (Measuring and evaluation of reduction gear unit for running test of Korea High Speed Train)

  • 이동형;서정원;문경호;최경진;최강윤
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2003년도 춘계학술대회 논문집
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    • pp.554-560
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    • 2003
  • The transmission systems of high speed train serve in the severe condition compared with those of other trains, namely, they have to transmit high power to run with high speed and they have to make maximum use of the limited space. To clarify the capability of reduction gear unit for Korea High Speed Train, torque and temperature, vibration on the reduction gear unit were measured and test data were analyzed. This paper reports test methods and test results that performed to verify reliability of reduction gear unit during running test of Korea High Speed Train. It is confirmed from these results that the performance of reduction gear unit has not any problem.

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닻 운용 시뮬레이션에 의한 선체운동 제어에 관한 연구 (A Study on the Control of Ship Maneuvering by the Simulation of Anchor Dredging)

  • 윤순동
    • 해양환경안전학회지
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    • 제8권2호
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    • pp.9-15
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    • 2002
  • Ship operators use anchor dredging for the collision avoidance or safety of ship handling in a harbour or narrow channel. This paper clarifies the technique of the anchor dredging known as a common sense for. the seafarers A mathematical model at low speed range is established for the estimation of ship motion under the assumed environment, simulate the advance speed , and turning ability under the anchor dredging or not. The results shows good agreement with the conventional seamanship and their experiences as follows. Ahead speed used the anchor dredging is slower(speed reduction ratio:40%) than the normal ahead speed and the stopping distance is shorter (distance reduction ratio:40%)than the normal ahead distance without the anchor dredging.. Turning speed used anchor dredging is slower(speed reduction ratio:72%)than the normal ahead speed and the tactical diameter is shorter(distance reduction ratio:24%)than the diameter by the normal turning without the anchor dredging.

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닻을 운용한 선체운동 제어 (A Study on the Control of Ship Motion using the Anchor Dredging)

  • 윤순동
    • 해양환경안전학회:학술대회논문집
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    • 해양환경안전학회 2002년도 추계학술발표회
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    • pp.127-134
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    • 2002
  • Ship operators are used to dredge anchor for the collision avoidance or safety of ship handling in a harbour or narrow channel. This paper clarifies the technique using tile anchor dredging known as a common sense for the seafarers. A mathematical model at low speed range has been established for the estimation of ship motion under the assumed environment , simulate the advance speed , and turning ability under the anchor dredging or not. The results shows good agreement with the conventional seamanship and their experiences as follows. Ahead speed used the anchor dredging is slower(speed reduction ratio:40%) than the normal ahead speed and the stopping distance is shorter (distance reduction ratio:40%)than the normal ahead distance without the anchor dredging. Turning speed used anchor dredging is slower(speed reduction ratio:72%)than the normal ahead speed and the tactical diameter is shorter(distance reduction ratio:24%)than the diameter by the normal turning without the anchor dredging.

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고속도로 노면표시 감속유도시설 효과평가 (Effectiveness of the Peripheral Transverse Line as Speed-Reduction Treatment on Korean Expressway Ramps)

  • 이성관;이기영;김석출
    • 한국도로학회논문집
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    • 제14권6호
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    • pp.85-92
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    • 2012
  • PURPOSES : Since expressways in South Korea are toll roads, many trumpet type interchanges exist, resulting in the installation of loop ramps very frequently. While the travel speed of the main lane is designed to be 100-110 km/h, the structure of a loop ramp is different and is designed for a minimum speed of 40 km/h. In fact, most of the actual travel speeds measured on the ramp exceed the designated speed, which has been a major problem in traffic safety. In this research, a type of pavement marking speed-reduction treatment called the "Peripheral Transverse Line" is installed on expressway loop ramps in order to study the change of driving speeds after the installation. METHODS : To verify statistically the change, this speed-reduction treatment has been installed on the Chungju interchange and the Yeoju junction. The driving speeds before the installation were compared with driving speeds both one month and five monthsafter the installation. RESULTS : As a result, the reductions of the average driving speeds after the treatment were statistically significant. More specifically, the average driving speeds of the Chungju interchange were reduced by 7.1-7.7 % for its tangent road section, and the speeds decreased by 8.5-9.5 % for its curve section. Similarly, in the Yeoju junction, an average speed reduction of 2.9-4.8 % for its tangent section was measured, along with 3.9% long-term speed reduction for its curve section. CONCLUSIONS : Since the pavement marking speed-reduction treatment has been partially proven to be effective from this research, we expect to expand this treatment and re-confirm the effect from a long-term perspective in the future.

Seasonal effectiveness of a Korean traditional deciduous windbreak in reducing wind speed

  • Koh, Insu;Park, Chan-Ryul;Kang, Wanmo;Lee, Dowon
    • Journal of Ecology and Environment
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    • 제37권2호
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    • pp.91-97
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    • 2014
  • Little is known about how the increased porosity of a deciduous windbreak, which results from loss of leaves, influences wind speed reduction. We hypothesized that, with loss of foliage, the wind speed reduction effectiveness of a deciduous windbreak decreases on near leeward side but not on further leeward side and that wind speed recovers faster in the full foliage season than in other seasons. During summer, autumn, and winter (full, medium, and non-foliage season, respectively), we observed wind speed and direction around a deciduous windbreak in a traditional Korean village on windward and near and further leeward sides (at -8H, 2H, and 6H; H = 20 m, a windbreak height). We used a linear mixed effects model to determine that the relative wind speed reduction at 2H significantly decreased from 83% to 48% ($F_{2,111.97}=73.6$, P < 0.0001) with the loss of foliage. However, the relative wind speed reduction at 6H significantly increased from 26% to 43% ($F_{2,98.54}=18.5$, P < 0.0001). Consequently, wind speed recovery rate between 2H and 6H in summer was two times higher than in autumn and ten times higher than in winter ($F_{2,102.93}=223.1$, P < 0.0001). These results indicate that deciduous windbreaks with full foliage seem to induce large turbulence and increase wind speed recovery rate on leeward side. Our study suggests that further research is needed to find the optimal foliage density of a deciduous windbreak for maximizing windbreak effectiveness regardless of seasonal foliage changes.

400 km/h급 고속철도의 소음저감을 위해 방음벽 상부에 설치하는 소음저감장치 개발에 관한 연구 (A Study on the Development of a Noise Reduction Device Installed at the Top of Noise Barrier for the 400 km/h Class High-speed Railroad)

  • 윤제원;김영찬;장강석;홍병국;엄기영
    • 한국소음진동공학회논문집
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    • 제23권9호
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    • pp.823-830
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    • 2013
  • The purpose of this study is to develop a noise reduction device installed at the top of noise barrier for further decreasing of noise level of 400 km/h class high-speed railroad. For this, the frequency spectrum of 400 km/h class high-speed railroad was analyzed through the field noise test, and the tuning frequency was determined to design a noise reduction device. The noise reduction device was designed to have noise reduction performance of at least 3 dB(A) using the prediction method(2D BEM) and through the laboratory test with the prototype. Finally, the outdoor test showed that this device could decrease noise level of 400 km/h class high-speed railroad even more than 3 dB(A).