• Title/Summary/Keyword: Gear box

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The Operation and Vibration Characteristics of Tail-Fan Performance Test System (테일팬 성능시험장치의 운용과 진동특성)

  • Song, Ken-Woong;Kim, Jun-Ho;Kang, Hee-Jung;Rhee, Wook;Sim, Jung-Wook
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.11a
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    • pp.508-512
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    • 2004
  • This paper described operation and vibration characteristics of 'Tail-Fan' performance test system. KARI(Korea Aerospace Research Institute) developed 'Tail-Fan' system as a kind of helicopter anti-torque system(ATS) and designed ATS performance test-rig for Tail-Fan system performance test. Test-rig consists of driving parts, supporting parts and rotating parts. For Tail-Fan system performance tests, firstly, test-rig operation tests were carried out for verification of design specifications. Secondly, natural frequencies of fan blade and test-rig were measured respectively. Lastly, to find the operation rotating speed for performance tests, vibration tests using accelerometers on tail gear box(TGB) were carried out. Through the fanplot and vibration test results, Tail-Fan performance test conditions to avoid a resonance were found and performance tests were well done safely.

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An Experimental and Numerical Study on Centrifugal Compressor Noise (원심압축기 소음측정과 계산에 관한 연구)

  • Sun, Hyo-Sung;Eom, Seung-Sin;Shin, Hyung-Ki;Lee, Soo-Gab
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.11a
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    • pp.119-124
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    • 2000
  • The 3-stage centrifugal compressor is used in order to measure the noise spectra of compressor, and analyze the results. Two cases are investigated for compressor noise components. Case I includes total system such as compressor, inter-cooler, motor, and Case II excludes cooling system. BPF tonal noise is important in compressor, and cooling system including inter-cooler contributes to broadband noise. Also, motor, gear box, and motor cooling fan are the second contributions to total compressor noise. Centrifugal compressor flow-field is calculated using two-dimensional grid and Navier-Stokes equations. Static pressure increases, and total pressure decreases, as air passes through the compressor components.

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A study on the Design of Drum Type Automatic Tool Changer (드럼형 자동공구교환장치의 설계에 관한 연구)

  • Choi, Hyun-Jin;Lee, Han-Gyu
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.19 no.7
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    • pp.52-59
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    • 2020
  • Automatic tool changers (ATCs) can be divided into drum and chain types. Drum-type ATCs contain a magazine, where the tools are mounted, and a cam gearbox, which swaps the tools via roller gear and grooved plate cams. Drum-type ATCs are advantageous in that the operating time for the tool magazine is more rapid than that of chain-type ATCs and the length of the unit is shorter. Thus, drum-type ATCs can be fabricated into various shapes and forms depending on the number of tools and the magazine size in accordance with machining center requirements and consumer demand. In particular, the price competitiveness of a machining center with a drum-type ATC is higher, while drum-type ATCs are more rigid with fewer parts, possibly reducing the need for regular servicing. This study aims to verify the structural stability and design validity of the magazine base, which is the main structure of a drum-type ATC, using finite element analysis. This study kinematically verifies the specifications of the selected drive motor and reducer and assessed the design of the cam gearbox. It also conducts a structural analysis of the roller camp, which is the core component of the cam gearbox, based on the results of the kinetodynamic analysis, thus validating the structural design.

Improving the Endurance Life of Deep Groove Ball Bearings for Automotive Transmission (자동차 변속기용 깊은 홈 볼 베어링의 내구수명 향상)

  • Baek, Hye-Yeon;Pyun, Jung-Min;Lee, Dae-Yong;Park, Tae-Jo
    • Tribology and Lubricants
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    • v.31 no.6
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    • pp.281-286
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    • 2015
  • Automotive transmission systems are assembled with a large number of gears and shafts, and rolling bearings are used to ensure their smooth operation. Gear oil in the gear box contains solid particles such as wear debris from contacting gears and metallic chips. This particle-enriched lubricating oil can cause premature failure of the rolling bearings. Research aimed at improving the service life of these rolling bearings has been confined mainly to design and lubrication of the inner/outer rings and the rolling elements. In this paper, we redesigned the shape of the cage pocket of a deep groove ball bearing to reduce the premature failure due to particle contamination. Test bearings are assembled with this new cage design containing a hole punched in the cage pocket. Endurance tests are carried out using the contaminated lubricating oil with miracle grid as hard particle. The duration and damaged bearing component shapes are compared for two different cages. The B10 life of bearing with new cage is increased by about 66% compared to the conventional cage. This is because the hard particles can be easily discharged through the pocket hole without staying for a long time in the lubrication regions. This greatly decreases abrasive wear and dents on the highly stressed ball bearing surfaces. Therefore, the cage design of this study, containing a pocket hole, can significantly delay the premature failure of rolling bearings and improve the endurance life.

A study on the cost state of the stow net Fishery (근해안강망어업경영의 원가실태에 관한 연구)

  • 박정호
    • The Journal of Fisheries Business Administration
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    • v.9 no.2
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    • pp.59-89
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    • 1978
  • The analyzed results of the actual state of stow net fishery based on the cost expended are as follows. According to the calculation of interests, the total cost of this fishery comes to ₩38,010,653 and in this account, the production cost comes to ₩35,477,198(93.3%), the material cost, 14,567,239(38.3%), the labour cost, 12,740,274(33.5%), the expenses, ₩8,169,685(21.5%), the commision and administration expenses, 2,533,455(6.7%). The expenses for this fishery are paid out as production costs, and the expenses for sale and administration expenses are the lowest of them, and the 93% of expenses are paid out as production costs. The ratio of cost element to 100% is as follow. The wages, 28.4%, fuel, 15.2%, repair, 11.6%, deprecation, 9.5%, fishing gear, 8.7%, ice, 6.1%, container(box for fish), 5.2% administration expenses, 5.2%, food, 3.5%, ship grar, 3.2%, public welfare, 1.7%, commision for sale, 1.5%, insurance for crew, 0.2%, taxes, 0.2%. This fishery is managed with the larger fishing boat than it was and so, it demands better crews with higher wages. In the former fishery, the search for fishing ground is very difficult with long navigation and great fuel consumption. when the weak fishing gears are used, the expenses for their repair and for their gears are greatly paid out. The unit costs of catches to each box come to ₩2.807(₩187 each kg). As the ratio of cost of sales comes to 86.7%and the ratio of interests comes to ₩5,850,812(13.3%), and so the net profit comes to 13.3% of total profits. According to above the ratio of cost of sales is shown as a universal validity, Asthe total expenses comes to 86.7% to the money on sales in the break-even point, the break-even point comes to ₩26,209,168 Accordingly for the profit control the account of production should be raised, and by the saving method of expenditure the break-even point should be brought down for the development of total profits.

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A Study on the Cost State of Medium Size Two-boat Trawler Fishery (이소인 중형기선저인망어업의 원가실태에 관한 연구)

  • 박정호
    • The Journal of Fisheries Business Administration
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    • v.8 no.2
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    • pp.1-19
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    • 1977
  • The results analyzed of the actual state of medium size two-boat trawler fishery based on the cost expended in 1975 are as follows: According to the calculation of interest, the total cost of this fishery comes to ₩ 55,353,807, and in this account, the production cost comes to ₩ 49,747,383 (89.9%) and the material cost comes to ₩ 27,027,662(48.8%), the labour cost comes to ₩ 10,381,013 (18.8%) the expenses, ₩12,338,708(22.3%) and commision and interest comes to ₩ 5,606,424 (10.1%). As above the fishery comes is 90% of production cost for the expense of production. The ratio of cost element to the total cost 100 is as follow: Fuel: 23.6%, allocation: 14.3%, fishing gear: 14.1%, boat repair: 13.0%, fish box: 8.5%, ice: 14.1%, commission: 6.9%, food cost: 4.5%, interest: 3.2%, transportation fee: 2.8%, consumption: 2.6%, tax: 2.5%, depreciation: 2.4%, administrative expense: 1.6%. The unit cost of catches to each box, including the interest, cames to ₩ 2,167 and not calculating the interest it comes to ₩ 2,098. The cost production to each kg comes to ₩ 114 including interest, without interest, it comes ₩110. When the production cost comes to 90.6%, it comes to 9.4% of total revenue. The reason which this fishery brings low income is that the boats are almost old and semi-diesel engine is used. So, fuel expense and repaire expenses needs too much. Acconding to above this fishery needs to replace new boat and new engine. And new are for this fishery needs to bring under cultivation in order to bring good income with the new method for this fishery. Specially, this fishery brings low income from July to September because of its rest from labour. And so, the expenses, item, and account of money, and the trust money the cost element are not showed in August.

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A Study on the Starter Control of the Turbo Generator (터보 제너레이터의 시동기 제어에 관한 연구)

  • 박승엽;노민식
    • Journal of Institute of Control, Robotics and Systems
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    • v.10 no.3
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    • pp.286-293
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    • 2004
  • This paper presents the result of a study on the starter control for a turbo generator. Because a starter in gear box type turbo-generator system is composed of gearbox and brush DC motor, it should be replaced with High Speed Generator(HSG)) in HSG type Turbo-generator. There-ore, it is necessary to design a new starting algorithm and starter. In gearbox type system, brush DC motor is rotated to the designed speed using low voltage-high current battery power. After brush DC motor speed is increased to several times by gearbox, gas turbine engine can be rotated to designed starting speed. If we implement a starter with High Speed Generator(HSG), it is necessary to drive high-speed generator to high-speed motor. High-speed generator with permanent magnet on rotor has a low leakage inductance fur driving high-speed rotation, and it is necessary high DC link voltage for inverter when High-speed generator is driven to high speed. This paper presents result of development of the boost converter for converting high voltage DC from low battery voltage and design of the inverter for controlling a high frequency current to be injected to motor winding. Also, we show performance of the designed starter by driving the turbo generator.

Optimal Design of the 4-cylinder Engine Rubber Mounts with Elastic Vibrations of Vehicle Body (차체의 탄성진동을 고려한 4기통 엔진 고무마운트의 최적설계)

  • 박철희;오진우
    • Transactions of the Korean Society of Automotive Engineers
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    • v.6 no.1
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    • pp.163-181
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    • 1998
  • In this study, the objective is determine the optimal design variable of engine mount system using the rubber mount of bush-type which is usually utilized in passive control to minimize vibrations of vehicle body or transmission from engine into body. The engine model adopted in this study is 4-cylinder, 4-stroke gasoline engine support- ed by 4-points. The system is modelled in 10 d.o.f.-rigid body motion of the engine & transmission in 6 d.o.f., elastic motion of vehicle body in 4 d.o.f.(1st torsional, 1st vertical and 1st & 2nd lateral bending vibration mode). To consider the elastic motion of vehicle body, find the eigenvalues and mode shapes of vehicle body by nodal testing and then determine the modal masses and stiffnesses of the body. The design variables of the engine mount system are locations, stiffness and damping coefficients of the rubber mounts(28 design variables). In case of considering the torque-roll axis for the engine, the design variables of the mount system are reduced to 22 design variables. The objective functions in optimal design process are considered by three cases, that is, 1) transmitted forces through engine mounts, 2) acceleration components of generalized coordinates for the vibration of vehicle body, 3) acceleration of specified location(where gear box) of body. three case are analyzed and compared with each other.

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Development of HILS System for Performance Evaluation of a Heavy Commercial Vehicle Hybrid Electric Power Steering System (대형 상용차량 하이브리드 전동식 조향 시스템 주행 성능평가를 위한 HILS 시스템 개발)

  • Yoo, Chunsik;Choi, Gyoojae
    • Transactions of the Korean Society of Automotive Engineers
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    • v.25 no.1
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    • pp.103-110
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    • 2017
  • Most commercial vehicles have adopted the hydraulic power steering system. To reduce fuel consumption and to improve steering controllability, a hybrid electric power steering system is being developed for commercial vehicles. In this study, the HILS (Hardware In the Loop Simulation) system equipped with a commercial vehicle hybrid electric power steering system was developed and the vehicle dynamic performance of a truck with the steering system was evaluated. The hybrid electric power steering system is composed of the EHPS motor pump, column mounted EPS system, and ball nut steering gear box for heavy commercial vehicles. The accuracy of vehicle models equipped with the HILS system was verified with comparisons between the simulation results and field test results. The road reaction forces of the steering system were generated from the vehicle model and verified using field test results. Step steering tests using the verified HILS system were carried out and the performance of a newly developed commercial vehicle hybrid electric power steering system was evaluated.

Process analysis of multi-stage forging by using finite element method (다단단조 CV JOINT 생산품의 유한요소해석)

  • Park, K.S.;Kim, B.J.;Kwon, S.O.;Moon, Y.H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2006.05a
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    • pp.399-402
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    • 2006
  • The outer race of CV(constant velocity) joint is an important load-supporting automotive part, which transmits torque between the transmission gear box and driving wheel. The outer race is difficult to forge because its shape is very complicated and the required dimensional tolerances are very small. Traditional warm and cold forging methods have their own limitations to produce such a complex shaped part; warm forging requires complex system with relatively higher manufacturing cost, while cold forging is not applicable to materials with limited formability. Therefore, multistage forging may be advantageous to produce complex shaped parts. In order to build a multistage forging system, it is necessary to characterize mechanical properties in response to system design parameters such as temperature, forging speed and reduction. For the analysis of formability of multistage forging process, finite element method(FEM) has been used for the process analysis. As a model case, a constant velocity (CV) joint forging process is analyzed by FEM, since CV joint has a complex shape and also its required dimensional tolerances are very tight. The data acquired by FEM is compared with operational forging data obtained from an industrial production line. Based on this comparative analysis, multistage forging process for CV joints is proposed.

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