• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.251-254
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• 2000

In this paper, we developed an automated program for the modeling and manufacturing of three-dimensional roller gear cams. A computer program employing the theory of gearing and coordinate transformation is developed for synthesizing and animating cam mechanisms. A method using wire frame modeling and shading by triangular element is presented, and effectively used for modeling of example with reduced computation time. Then a module for generation NC program for a five-axis CMC machine to manufacture roller gear cam is established.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.6
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• pp.631-637
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• 2013

The characteristics of involute gear pump with eccentric gap between gear tip and housing have been studied in terms of volumetric flow rate and/or flow efficiency. The analysis has been done with FLUENT/R-13 employing with k-e model for the turbulent flow under the given conditions of rotational velocity, gap distance and outlet pressure. The effect of parameters continues to be shown for the eccentric gear as same as for the concentric gear such that the volumetric flow rate (volumetric efficiency) increases as the increases of rotational velocity and decrease of gap distance and of outlet pressure. In the meantime, the shape of pressure build-up appears to be exponentially increase as gap distance decreases at upstream position. The pressure is rapidly developing in the upstream and remains almost constant thereafter in the downstream of circumferential flow path. This typical characteristics becomes more profound as eccentricity increases. The pump performance for the eccentric gear pump with minimum gap distance shows better than its concentric counterpart. However, it shows not for the concentric pump with minimum gap distance. Therefore, the gap reduction due to eccentricity may be positive for pump performance.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1262-1265
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• 2004

A cycloidal speed reducer is a type of the speed reducers of machinery. The cycloidal speed reducer consists of two cycloidal plate gears, housing roller gear, input shaft, output pin and shaft, and eccentric bearings. Especially the cycloidal plate gear has the peculiar parts of the teeth, because of gearing with the housing roller gear that has the several rollers on the circular line. And then all teeth on the cycloidal plate gear can be designed to contact with the rollers on the housing roller gear at the same time. Therefore the cycloidal plate gear has always contact motion with rollers and the force is interacted between roller gear with cycloidal plate gear. Because the contact force and friction force must be required to improve the accuracy in design procedures of cycloidal speed reducers, this paper presents a force analysis considered friction effect approach derived by static force equilibrium condition, geometrical adaptation, instant velocity center method and relative velocity method.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.3
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• pp.234-239
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• 2013

There are many types of speed reducer for industrial uses. However the cycloid speed reducer is widely used in manipulators based on excellent performance of low backlash, high reduction ratio and compact size. It is essential to use precision speed reducer for accuracy of position controls on robot systems and electric vehicles. The cycloid speed reducer has a eccentric rotating motion and offset to avoid some problem of assembly, so it has a disadvantage for vibration. In this paper, a multi-body dynamic model is developed for a cycloid speed reducer and the dynamic behaviors of the reducer are investigated. The cycloid speed reducer consists of cycloidal plate gears, housing gear, input shaft, output pin and shaft, and eccentric bearings. Using a CAD program, each component of cycloid reducer is modeled based on the offset and eccentric. Multi-body simulations using Recurdyn and test using a rig tester are performed. As a result, the pin reaction force and the amplitude of housing displacement are increased by the larger offset and smaller eccentric value of cycloid reducer.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.1
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• pp.154-162
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• 1991

In this study, the simulation program is developed where the tooth profile error in internal gear shaping is calculated considering several factors which affect it. This factors are the circular feed of the pinion cutter, the interference by the geometric conditions of the cutter and the internal gear, the deviation from the theoretical involute profile of the cutter and the eccentricity of the cutter and the internal gear. With this program, the effects are investigated which the geometric conditions and the cutting conditions in internal gear shaping have on the tooth profile error of the internal gear. The condition for the minimization of it is derived and then the results of simulation are adequately verified by measurements of internal gears cut by a pinion cutter.

• Journal of Biosystems Engineering
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• v.15 no.2
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• pp.88-98
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• 1990

The purpose of this study was twofold : first, to reduce as much as possible the shaking moments of the crank-type transplanting mechanism of walking-type rice transplanters, and second, to evaluate whether or not a crank-type transplanting mechanism, if its shaking moment is reduced, can be used in riding-type transplanters for high speed transplanting operations. For these purposes, kinematic and force analyses of the currently available crank-type transplanting mechanisms were made and their results were compared with those observed by experimentation. The degree of shaking moment effect was also estimated Various efforts to minimize the shaking moments led to the development of a crank-type mechanism with a balancing gear, in which an eccentric balancing gear is combined into the driven link axis. Analysis of the developed mechanism showed that about 20% of the shaking energy can be reduced and about 40% of reduction in peak shaking moment can be obtained when comparing with those obtained without the balancing gear. It was concluded that crank-type transplanting mechanisms can be used for high speed operations with a forward speed of 0.9-1.2m/s if the balancing gear is additionally mounted. However, further considerations must be made to solve the space constraints in relation to the structural frame of riding type of rice transplanters.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.266-270
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• 2006

Noise reduction the noise of a high precision multi-stage gearbox applied at the industrial robot is investigated by experiment such as the modal test and the signal analysis. The signal analysis performed with the waterfall plot representing the power spectrum as a function of the rotating speed. An eccentric load is installed at the gearbox in order to organize similar condition used in the industrial robot. Exciting sources are found out by the waterfall plot, and then the main factor to make the noise is distinguish. For the low-noise gearbox, the gear design parameter is modified and this gearbox is experimented in the same procedure. The results of the test show the noise level of gearbox reduced.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.11
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• pp.1217-1224
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• 2009

This paper presents a finite element (FE) analysis of the torsional rigidity of a two-stage cycloid drive. The cycloid disk makes contact with a number of pin-rollers simultaneously and eccentric shafts transmit not only torque of the spur gear stage to the cycloid disk, but also that of the cycloid disk to the output disk. Contacts between the disk and pin-rollers are simplified as linear spring elements, and the bearing of eccentric shaft is modeled as a rigid ring that has frictional contact to the disk and an elastic support. FE analysis for an ideal solid cycloid drive was performed and verified by a theoretical calculation. Accurate contact forces were then estimated by iterating between FE analysis for contact forces and Hertz theory calculations for nonlinear contact stiffness. In addition, torsional rigidity of the cycloid drive is analyzed to show that the bearing and nonlinear Hertz contact theory should be considered in analysis and design of a cycloid drive, which was verified with experiments. Finally, the effects of contact stiffness, bearing stiffness and cycloid disk structural stiffness according to the cycloid disk rotation on the torsional rigidity were investigated.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.11
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• pp.1057-1063
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• 2012

A cycloid speed reducer is a type of the speed reducers. The cycloid speed reducer has a eccentric rotating motion and offset to avoid some problem of assembly, so it has a disadvantage for vibration. In this paper, a multi-body dynamic model is developed for a cycloid speed reducer and the dynamic behaviors of the reducer are investigated. The cycloid speed reducer consists of cycloidal plate gears, housing gear, input shaft, output pin and shaft, and eccentric bearings. Using a CAD program, each component of cycloid reducer is modeled based on the offset and multi-body simulations are performed using Recurdyn. As a result, the pin reaction force and the amplitude of bearing displacement are increased by the offset.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.3
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• pp.104-109
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• 1999

In order to design and predict the performance of the harmonic side drive motor, it is necessary to analyze the torque generated by the structure. In this paper, an analytical model is proposed for design. Conformal mapping is used to model the capacitance and torque of the motor as a function of the rotor angular position with two-dimensional approximation. Then the result of conformal mapping analysis is verified with F.E.M result.