• Title/Summary/Keyword: Reduction Gears

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The effect of addendum modification on bearing load in marine reduction gears (박용함속치차장치에서 전위가 베어링하중에 미치는 영향)

  • 민우홍
    • Journal of Advanced Marine Engineering and Technology
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    • v.8 no.2
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    • pp.74-80
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    • 1984
  • In the reduction gears for marine propulsion engine such as turbine or high speed diesel engine, the standard involute double helical gears are generally used. However the addendum modification gear can be used in the reduction gear as it has flexibility for gear design on the tooth strength, scoring and operating noise. In this case, the determination of gear shaft bearing load is difficult by the alternation of operating pressure angle. In this paper, the formulas of bearing load according to the arrangements of the reduction gears are derived and the diagrams of operating pressure angle according to the modification coefficient are presented.

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Analysis of the Reduction Gear in Electric Agricultural Vehicle

  • Choi, Won-Sik;Kwon, Soon-Goo
    • Journal of the Korean Society of Industry Convergence
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    • v.21 no.4
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    • pp.159-165
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    • 2018
  • In electric agricultural machine a reduction gear is needed to convert the high speed rotation motion generated by DC motor to lower speed rotation motion used by the vehicle. The reduction gear consists of several spur gears. Spur gears are the most easily visualized gears that transmit motion between two parallel shafts and easy to produce. The modelling and simulation of spur gears in DC motor reduction gear is important to predict the actual motion behaviour. A pair of spur gear tooth in action is generally subjected to two types of cyclic stress: contact stress and bending stress. The stress may not attain their maximum values at the same point of contact fatigue. These types of failure can be minimized by analysis of the problem during the design stage and creating proper tooth surface profile with proper manufacturing methods. To improve its life expectation in this study modal and stress analysis of reduction gear is simulated using ANSYS workbench based on finite element method (FEM). The modal analysis was done to understand reduction gear deformation behaviour when vibration occurs. FEM static stress analysis is also simulated on reduction gear to simulate the gear teeth bending stress and contact stress behaviour.

An Experimental Study on the Power Transmission Efficiency and Frictional Noise of $MoS_2$-Bonded-Film Coated Reduction Gears (접착형 $MoS_2$고체윤활피막이 코팅된 감속기의 동력전달효율과 소음 특성에 관한 실험적 고찰)

  • 윤의성;공호성;한홍구;오재응
    • Tribology and Lubricants
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    • v.12 no.3
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    • pp.107-114
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    • 1996
  • MoS$_{2}$ bonded film was applied to reduction gears, and its lubricating properties were experimentally evaluated in terms of the power transmission efficiency and the frictional noise with a dynamo-typed gear test rig. Tests were performed in both oil lubrication and dry condition where the rotating velocity and loading torque were varied. In dry condition, MoS$_{2}$ bonded films effected the power transmission efficiency to increase about 5%, and the frictional noise level to decrease about 6 dB under the test operating conditions. It well proved that MoS$_{2}$ bonded films were a very effective solid lubricant for reduction gears. In oil lubricating conditions, the frictional properties of the coated gears were mainly governed by the lubricating oil, and lubricating effects of MoS2 bonded films were not evident. The result suggested that lubricating effect of MoS$_{2}$ bonded films would be limited to prevent a damage of reduction gears in the initial run when they were used in oil lubrication conditions.

Mass Reduction of Transmission Gears for Commercial Vehicles (상용차용 변속기 기어의 경량화)

  • Shin, Yoo-In;Shin, Sung-Hwan;Oh, Tae-Il;Suh, Jeong-Se;Song, Chul-Ki
    • Journal of the Korean Society for Precision Engineering
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    • v.29 no.3
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    • pp.319-323
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    • 2012
  • Transmission is one of the important pars to transmit power from engine to wheels. Mass reduction gears can make the engine power requirement reduce, and can make dynamic performance and fuel efficiency of vehicle improve. Transmission gears are modified for mass reduction without changing their tooth shapes, face widths, and modules by using shape optimization and re-check process. Also structural stability is verified by FEA.

A Study on the Forced Torsional Vibration of Engines Shafting Systems with Non-linear Elastic Couplings (비선형 탄성커플링을 갖는 기관축계의 비틀림강제진동에 관한 연구)

  • 박용남
    • Journal of Advanced Marine Engineering and Technology
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    • v.22 no.3
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    • pp.328-336
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    • 1998
  • Marine reduction gears are usually used to increase the propulsion efficiency of propellers for ships powered by medium and small sized high speed diesel engines. Most of shaft systems adopt flexible couplings to absorb the transmitted vibratory torque from the engines to the reduction gears and to prevent the chattering phenomenon of reduction gears. However some elastic couplings show non-linear characteristics due to the variable torque transmitted from the main engines and the change of ambient temperature. In this study dynamic characteristics of flexible couplings sare investigated and their effects upon various vibratory conditions of propulsion systems are clarified. A calculation program of torsional vibration for the propulsion systems are clarified. A calculation program of Results of the program developed are compared with ones of the existing linear method and propulsion systems with the elastic couplings the transfer matrix method is adopted which is found to give satisfied results.

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Developing Planetary Gear Reduction Design Software for the Planetary Gear Design and Durability Strength Analysis of Armored Vehicle's Transmission (장갑차용 트랜스미션의 유성기어 설계 및 내구 강도 분석을 위한 유성기어 감속기 설계 소프트웨어의 개발)

  • SinHyun Kang;SungHo Park;YonSang Cho
    • Tribology and Lubricants
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    • v.39 no.5
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    • pp.173-182
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    • 2023
  • The composite planetary gear reducer, a power transmission component of armored vehicles, operates at a high torque and is used in severe environments such as mountain, gravel or unpaved roads. Therefore, they must be designed and manufactured to have high durability. To design such a planetary gear reducer, there are numerous specifications to validate, such as selecting the module and the number of teeth of each gear satisfied the requirements, and calculating gear specifications and durability strength. Because planetary gears constitute a combination of several gears, there are many restrictions and interferences in selecting the number of teeth and addendum modification coefficients, and designing the tooth shape. Developing an auto design program is necessary to design various planetary gears more conveniently and quickly. In this study, a planetary gear reducer design software, widely used in various machines and armored vehicles, was developed. This design software can automatically select the number of teeth and modules of the gears, calculate specifications and quickly evaluate its fatigue durability strength and scoring failure according to the planetary gear reducer design theory.

The Critical Speed Analysis of the Differential Planetary Gear Train of a Concrete Mixer Truck Mixer Reducer (콘크리트 믹서 트럭용 믹서 감속기의 차동 유성 기어 트레인에 대한 위험속도 해석)

  • Bae, Myung Ho;Bae, Tae Yeol;Kim, Dang Ju
    • 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.

Development of High-Ratio Planetary Reduction Gears Applied Differential Ring Gear Type (차동 링기어 방식의 고비율 유성기어 감속기 개발)

  • 박규식;이기명;김유일
    • Journal of Biosystems Engineering
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    • v.22 no.4
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    • pp.497-502
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    • 1997
  • Automation facilities of greenhouses have been continuously developed. However, the conventional two-stage worm gear reducer reveals some problems, including low transmission efficiency. The worm gear reducer also have some difficulties in manufacturing and short life. Therefore, this study was performed to develop a planetary gear reducer, having a high Sear reduction ratio and high torque transmission efficiency. The planetary gear system consisted of a fixed ring gear and a 2-teeth differential ring gear turning slow, as the planetary pinion orbits fast around the fixed ring gear. The developed gear system can achieve a high speed reduction rate at one stage. The reducing system was employed to the greenhouse ventilation system. The reducer has the transmission efficiency of 70.5%, 2∼3 times longer life time, and twofold roll-up torque at an affordable price, comparing with conventional reducers. This reducer can be also applied to many industrial equipments, such as industrial crane, hoist, elevator and gondola etc.

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

  • Kim, Jae Chul;Ji, Hae Young;Lee, Kang Ho;Moon, Kyung Ho;Seo, Jung-Won
    • Journal of the Korean Society for Precision Engineering
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    • v.30 no.7
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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.

A Study on the Sliding Wear Rate Calculation in Spur Gears (Spur Gear의 미끄럼 마멸률에 관한 연구)

  • 김태완;문석만;구영필;조용주
    • Tribology and Lubricants
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    • v.16 no.5
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    • pp.357-364
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    • 2000
  • In this study, the sliding wear in spur gears, using Archard's wear model, is analyzed. Formulas of tooth sliding wear depth along the line of action are derived. The tooth profile is modified Id make a smooth transmission of the normal loads and the cylinder profile for reducing the pressure spike is suggested. The sliding wear rate is calculated with these profiling results. We expect these modification methods to contribute to the reduction of sliding wear not only in the root, but the tip of tooth and tooth edge.