• Journal of the Korean Society for Precision Engineering
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• v.22 no.12 s.177
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• pp.108-116
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• 2005

Transplanting accuracy of a rice transplanter mainly depends on the trajectory of the hoe for picking, conveying and transplanting of seedlings as well as the return motion. The trajectory can be decided and prescribed to be suitable in treating seedlings fur a prevailing soil condition. For the purpose of the transplanting accuracy, the design of a transplanting mechanism would be carried out using a planetary-gear-train system instead of the four bar linkage system. In this study, a design method of transplanting mechanism is theoretically proposed by synthesizing a noncircular planetary-gear-train system fur the tool (hoe) to trace a prescribed trajectory. The method utilizes an optimization approach to decide the lengths of an arm and a tool, the inverse kinematics to figure out the configuration angles of the two links, the roll contact condition in transmitting motion between the gears, and a linearization approach to obtain the shapes of the gears. Based on the proposed method, the shapes of the gears and the lengths of the tools of the planetary-gear-train system are determined fur three prescribed trajectories. A kinematical simulation with a commercialized package program is also carried out to confirm that the gear-train system synthesized with the proposed method is able to trace the prescribed trajectory.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.11 s.176
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• pp.111-117
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• 2005

The vibration problems associated with gear coupled rotors have been the focus of much engineering work. These systems are complex and difficult to analyze in that they have the problems associated with conventional rotors plus those additional problems associated with the gear couplings. This paper examines the problems peculiar to the gear mesh. Because of the meshing action of gears, the elasticity of the gear teeth introduces time-varying stiffness coefficients into the governing equations of motion. This means that system response must be thought of in terms of Mathieu-type equations, where multiple-frequency response occur due to the periodic coefficients. The meshing action of the gears also couples the lateral and torsional gear motions. Gear errors, such as tooth profile and spacing errors, produce forces and torque that excite the system at multiple frequencies, some of which are much higher than shaft rotational speed. To investigate how to the time-varying stiffness in the gear teeth and the gear errors act one the dynamic response of the gear coupled rotors, a three-dimensional dynamic model with lateral-tortional oscillation is developed. The harmonic balance technique is employed to solve this mathieu-type problem.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.4
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• pp.358-364
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• 2012

This work dealt with dynamic characteristics of spur gear and helical gear system to understand the gear vibration and noise. To find out dynamic characteristics in the gear system, a finite element model and an analytic model for the gear system were used. Using the models, the natural frequency and mode-shape characteristics of spur gears and helical gears were calculated. Two models show that natural frequencies of helical gears were lower than those of spur gears. Mode-shape characteristics of gear pairs by analytical model and some issues of finite element modeling were also discussed. Impact test was used to validate the finite element model.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.274-279
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• 2009

Reduction Gear Box where from productive site uses the gear with power delivery with high mechanical efficiency of power a deceleration and as the mechanical element union product which has the velocity ratio which is various together is produced with the power occurrence motor and leads gets a high driving force is plentifully used. The above occurs from gear drive issue sound Whine, Noise and Vibration as occurring from the rim process which the gear will bite mainly is delivered with the case etc. gear drive whole which leads the axis and the bearing. The productivity falls with the going straight rate decrease which with like this problem point is caused by with rework the problem point where the cost of production rises under improving boil many kinds analyzed the plan and investigates the resultant acceleration sensor which and a frequency analysis system and was made to apply.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.12
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• pp.157-164
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• 1995

Straight belvel gear is used mainly for steering system, final reduction and differential gear in the automobile. The more high load, high velocity driving bevel gear, the more unsafe and unpleasant. In thid study, we get a kinematic equation by modelling straight bevel gear pair with simple elastic system, the dynamic characteristic analysis about this system, we got the dynamic load factor of tooth surface. Comparing the value of dynamic load factor by calculation with the measured value of Terauchi's experimental results is similar. We think it useful to analysis the vibration and the noise of straight bevel gear in operation with the analytic method of dynamic load of straight bevel gear using in this study.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.3
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• pp.88-96
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• 1998

The rattle noise is the most significant in many kinds of manual gearbox nioses, which is generated at the idle stage of the engine operation. The main torsional vibrat- ion source of the driveline is the fluctuation of the engine torque. The gear rattle is impacts generating in the backlash of the free gear due to this torsional vibration. Many researchers reported the clutch torsional characteristic optimization method to reduce the idle gear rattle but only few of them give sufficient consideration to the system parameters like gear backlash, drag torque, system inertia, inertia distribution, engine torque fluctuation, idle engine rotation speed, and accessory load. In this paper, influence rate of system parameters on the gear rattle is presented and counterplans like backlash reduction, drag torque increase, inertia addition, inertia distribution modification and engine torque characteristic control are suggested.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.5
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• pp.12-22
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• 2008

In this study, the dynamic characteristics for the wheel-type landing gear system of helicopter have been analyzed. Nonlinear multi-body dynamic models of the landing gear system are constructed and the equations of motion, kinematics and internal forces of shock strut are considered. In addition, flexibility effect of the wheel axle with equivalent beam element is taken into account. General purpose commercial finite code, SAMCEF which includes MECANO module is applied. The results of dynamic simulation for various landing and weight conditions are presented and compared with each other. Based on the results, characteristics of impact dynamic behaviors of the landing gear system are practically investigated.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.5 no.3
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• pp.40-49
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• 1996

The problem related to the rotational vibration at steering wheel end of passenger cars during high speed driving is investigated. to analyze vibration of steering wheel, a steering system of passenger car is modelled in twelve degrees of freedom including backlash effect of rack and pinion gear system. The one degree of freedom system with backlash in investigated by the analytical method. Consequently the skeleton curve and the frequency response curves are computed. The steering system is analyzed by the numerical simulation using the 4th order Runge-Kutta method, the obtained results are compared with the experimental data. Also the effects of the change of rack gear tooth stiffness and backlash on the acceleration level of steering wheel are investigated. As a result, it can be found that the acceleration level of steering wheel becames lower as the rack gear tooth stiffness becames higher, and that acceleration level becames high as the magnitude of backlash between rack and pinion gear increase.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.759-762
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• 2002

A preliminary design process in the multi-stage gear drives design is important part. a preliminary design support system which run efficiently the design is developed with fuzzy expert system. the system automatically generate the mechanism of multi-stats gear drives and select a candidate mechanism by the general expert rule and sorting using fuzzy expert system. the preliminary mechanism design of multi-stage gear drives have a short execution time, add accuracy in a preliminary design considering volume, cost, power and efficiency in preliminary, a design efficiency is increased and a preliminary design have a elasticity using a weight on variable's sorting mechanism.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.311.2-311
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• 2002

Even through the problem of misalignment is of great importance, not much work has been reported in the literature on the effect of misalignment on the vibrations of the gear-bearing systems. Therefore, the nonlinear dynamic characteristics of the gear driving system due to misalignment are investigated in this work. Transmission error for helical gear and bearing nonlinear stiffness is calculated. (omitted)