• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1042-1048
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• 2007

This work analytically investigated the radiated noise of a helical gear-housing system due to the excitation of helical gears. The helical gears were modeled as a 12-degree of freedom mass-spring-damper system; the shaft was modeled as a rod, a beam, and a torsional shaft; and the gear housing was modeled as a clamped circular plate with viscous damping. The modeling of this system used transfer matrices for helical gears, shafts, and bearings. Damping for both the bearings and the plate were obtained by modal testing. For the evaluation of noise, sound pressure from the plate due to the force and the moment in both radial and tangential directions was analytically derived by the Rayleigh integral. The analytical derivation and parameters from the experiment were applied to an analysis of noise for the two sets of helical gears with differing gear ratios. The analysis showed that the moment excitation in both helical gears contributed more to the noise of the plate than axial force excitation.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.158-161
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• 2005

In this paper, the precision electric discharge machining technology, the powder electric discharge machining technology, is applied to making a cold forging die for making the helical type of clutch gear. Various working conditions are investigated with emphasis on reduction of the electrode wear and enhancement of the surface roughness. Through the research work, the key technology of making the helical gear forging dies is achieved.

• 한국기계가공학회지
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• 제18권6호
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• pp.91-97
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• 2019

Rotating machining unit is a revolutionary product that can process worm shaft or spiral shaft with fast and precise, a rotary type cutting tool, which is attached to automatic lathe and processes spiral groove on outer circumference of round bar. In this work, a study on micro tooth shape modification method of driving gear train in the rotating machining unit was presented. To observe the effect on power transmission characteristics of the driving gear pair, visualize the gear meshing condition and the load distribution on the gear teeth by using the professional gear train analysis program RomaxDesigner. By comparing the repeated analysis results, the effect of micro tooth shape modification on power transmission characteristics on driving gear can be summarized. The optimized gears were fabricated and measured by precision tester as a validation in this research.

• 한국생산제조학회지
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• 제7권4호
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• pp.96-103
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• 1998

With the advance of processing technology , so as to spare fuel, piston heads used in automobile reciprocating engine have complex 3-dimension, with respect to shape such as ovality, profile, eccentricity, offset, recess. Therefore, coming out of the existing process work used master cam. the process work is performed using a CNC lathe. For a precision processing, the processing work is need to make study of high speed feed gear synchronized with the rotative speed of main spindle. And then the high speed feeding system must maintain high dynamic stiffness, high speed and high positioning accuracy . In this paper, in order to achieve high speed cutting tool feeding. The linear brushless DC motor is used for satisfying this process work. The ball bush and turicite is used as the guidance of the feed gear system. Also linear encoders, digital servo amplifiers and controller are used for controlling driving motor. This paper presents the design and simulation of the new tool feed system for noncircular machining.

• 수산해양기술연구
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• 제35권4호
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• pp.343-352
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• 1999

Because stow net being used in now is doing throwing net and hauling net through a ship's side, the work is very complicated and the fishing boat needs many seamen and it could cause a loss of lives and ship in stormy weather. We are now using small mesh size 36~500mm and it even catches young fish, so we call it the fishing gear of resource reduction type.Therefore we must make manpower reduction in automatic operation, safe operation of throwing net and hauling net in the stern and the stern-typed stow net of resource management using large mesh. And we performed three-typed model tests to examine the fishing gear. The obtained results are as follows;1. The fishing gear being used in the ship's side type stow net has inappropriate standard and arrangement of the net, resistance increase of the fishing gear and frequent breakdown of the net.2. To supplement the fault of A-typed stow net, we schemed fishing gear developed as both B-type(12-seamed net) and C-types(8-seamed net) of the stern-typed stow net. 3. In model tests, C-typed model net(mesh size 40~1,600mm) was proved good fishing gear because the resistance in accordance with the flowing speed was comparatively small and it's mouth area was broad. 4. A-typed stow net had the spreading device attached to side panel of the net, but the stern-typed stow net had the spreading device consisted of 4 lines far behind about 6m from side panel of the net mouth. In the flowing speed 2knot, the spreading condition of fishing gear was proved batter than the former.

• Advances in aircraft and spacecraft science
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• 제7권5호
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• pp.459-473
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• 2020

The aircraft nose landing gear (NLG) can suffer of an unstable vibration called shimmy that is responsible of discomfort and of fatigue stress on the gear strut components. An adaptive controller is proposed in this paper to cope with the aforementioned problem. It is based on a method called Modified Simple Adaptive control (MSAC) which is able of governing the NLG motion by using a feedback signal that relies on just one output of the plant. The MSAC only asks for the passivity of the controlled plant. With this aim, a parallel feedforward compensator is employed in this work to let the system satisfies the almost strictly passivity (ASP) requirements. The nonlinear equations that govern the aircraft NLG shimmy vibration behavior are used to analyzed the controlled system transient response undergoing an initial disturbance and taking into account different taxiing speed values.

• 한국생산제조학회지
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• 제9권1호
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• pp.30-37
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• 2000

In this paper rapid prototyping and precision casting technology have been developed for the manufacturing of inlet gear box of an airplane, Rapid prototyping is a new prototyping technology that produces complicated parts directly from three-dimensional CAD data with a high efficiency and has been extensively applied to various manufacturing processes. In the present work Selective Lase Sintering(SLS) system is utilized in order to manufacture prototype of the inlet gear box. Prototyping technology using SLS is also investigated from the viewpoint of accuracy. Using the SLS master the casting products are manufactured through several processes such as : vacuum casting lost wax shell casting and investment cast-ing. The shrinkage characteristics of wax and cast iron in the casting procedures are considered and then reflected to the design procedure so that the accuracy of the product is improved consequently.

• 한국소음진동공학회논문집
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• 제27권1호
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• pp.36-42
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• 2017

Helical gear excitation is transmitted to a gearbox through the shafts and bearings and the vibration of the gearbox radiates the noise in the air. Therefore gearbox modeling is essential to evaluate the gear noise. This work deals with vibration and acoustic analysis of a cylindrical shell-type gearbox with/without holes excited by helical gears and focuses on the development of the simple gearbox model. To do so, helical gears and bearing forces are calculated. Gearbox with/without holes is modeled by the aluminum end plates and PMMA cylindrical shell body. The vibration mode and the forced harmonic response were calculated by the commercial FE software and the end plate of the gearbox is more contributed to vibration than the body. Acoustic analysis was also conducted by the commercial acoustic software and a cylindrical shell type gearbox with/without holes has the similar vibro-acoustic characteristics.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1069-1074
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• 2008

Tool condition monitoring (TCM) is crucial for improvement of productivity in manufacturing process. However, TCM techniques have not been applied to monitor tool failure in an industrial gear shaving application. Therefore, this work studied a statistical TCM method for monitoring gear shaving tool condition. The method modeled the shaving process using beta probability distribution in order to extract the effective features. Modeling includes rectifying for converting a bi-modal distribution into a unimodal distribution, estimating parameters of beta probability distribution based on method of moments. The usefulness of features obtained from the proposed method was evaluated and discussed.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1996년도 추계학술대회논문집
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• pp.174-184
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• 1996

Two methods for cold extrusion processes to produce an axisymmetric steel gear blank are investigated for comparing each other. The "classical" forming method consisting of four operations is selected first to be simulated using the rigid-plastic finite element method and uses single-die presses. The other using a fully automated transfer headers can produce the final part without interannealing. The final products must be checked at the design criteria such as area reduction, the extrusion ratio and punch diameter to depth ratio, especially punch buckling by simulations. FEM analysis is performed mainly for strain distribution, both process sequences are proved to have proper charicteristics suitable for each production method in terms of maximum load. Those simulation results will provide good design criteria in the future work to advance the manufacturing process.