• 한국소음진동공학회논문집
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• 제24권5호
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• pp.407-413
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• 2014

The diesel engine and reduction gear combination is one of the common propulsion system in a naval vessel. Since the diesel engine has torsional vibration caused by reciprocating motion of the mass and gas pressure force of the cylinder, high cycle torsional fatigue can be occurred. Therefore, ROK navy restricts the maximum stress of the propulsion shaft according to MIL G 17859D. In this paper, the root cause for the failure of the diesel engine and reduction gear connecting shaft occurred in typical naval vessel is investigated based on the measured bending and torsional moment according to MIL G 17859D procedure.

• 한국기계기술학회지
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• 제13권4호
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• pp.137-141
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• 2011

Driving mechanism, the central part of a robot, was designed in this study. Power for the motive drive was acquired by directly connecting the motor shaft in worm shape of the low-end DC motor, car window motor, to a decelerator. The decelerator consists of a worm gear to receive power from the motor shaft, a pinion gear to be connected in line with the worm gear, and an output shaft to be engaged to the pinion gear. Motion driving is achieved by the power from the motor shaft with the designed gears, transferred to the deceleration mechanism and to the output gear.

• Journal of Magnetics
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• 제18권2호
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• pp.207-211
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• 2013

In a coaxial magnetic gear, bridges connecting separate pole pieces are useful for fabrication and also improve mechanical reliability. However, they have a negative influence on electromagnetic performance parameters such as transmission torque and iron loss. This paper investigates the effect of stationary pole pieces connected by bridges on the electromechanical characteristics. The bridge type and thickness are the main parameters influencing the performance of a coaxial magnetic gear. The inner, center, and outer bridge types each show the best performance in terms of different characteristics. However, for any bridge type, an increase in the bridge thickness reduces the overall electromagnetic performance, except for the torque ripple, and improves the overall mechanical performance, including the deformation, von Mises stress, and natural frequency of the stationary part.

• 한국기계가공학회지
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• 제20권3호
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• pp.92-99
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• 2021

An automatic transmission, which consists of several decks of planetary gear sets, provides multiple speed and torque ratios by actuating brakes and clutches (mechanical friction components) for connecting central members of the planetary gear sets. The gear set consists of the sun gear, the ring gear, and the carrier supporting multiple planet gears with pin shafts. In designing a new automatic transmission, there are many steps to design and analyze: gears, brakes and clutches, shafts, and other mechanical components. Among them, selecting thrust bearings that not only allow the relative rotation of the central members and other mechanical components but also support axial forces coming from them is important; doing so yields superior driving performance and better fuel efficiency. In selecting thrust bearings, the magnitude of axial forces on them is a critical factor that affects their bearing size and performance; its results are systematically related to the direction of the helical angle of each planetary gear set (a geometric design profile). This research presents the effects of the helical angle direction on the axial forces acting on thrust bearings in an automatic transmission consisting of planetary gear sets. A model transmission was built by analyzing kinematics and power flows and by designing planetary gear sets. The results of the axial forces on thrust bearings were analyzed for all combinations of helix angle directions of the planetary gear sets.

• Journal of Mechanical Science and Technology
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• 제20권6호
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• pp.770-781
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• 2006

This paper defined design constraints for the compound CVTs (continuously variable trans-missions) by combining power-circulation-mode CVTs and power-split-mode CVTs, which were proposed for connecting 2K-H I-type differential gear to V-belt-type CVU (Continuously Variable Unit). The design constraints are the necessary and sufficient conditions to avoid geometrical interferences among elements in the compound CVTs, and to guarantee smooth assembly between the power-circulation-mode CVT and power-split-mode CVT Two com-pound CVTs were designed and manufactured in accordance with the design constraints. With these compound CVTs, theoretical analysis and performance experiments were conducted. The results showed that the design constraints were valid and effective design method, and that the designed compound CVTs had the improved performance.

• 한국소음진동공학회논문집
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• 제18권1호
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• pp.80-86
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• 2008

In this study. the noise sources were identified and the noise and vibration were reduced for an industrial forklift. To identify the noise sourses, noise signals were measured by a microphone on a driver seat and these signals were analyzed with a waterfall plot. For this purpose, the gear mesh frequencies from the gear box of a reducer were not only investigated but noise/vibration sourses of an electric motor were also examined. Furthermore, the frequency response functions were obtained to confirm the vibration and noise sourses. It was found that severe vibration and noise were generated in the casing and the connecting part of the reducer. The severe vibration and noise could be reduced by a structure modification.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 춘계학술대회 논문집
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• pp.456-461
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• 2014

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1345-1348
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• 2005

We designed the compound CVT (Continuously Variable Transmissions) by combining power circulation mode CVT and power split mode CVT, which have been proposed for connecting 2K-H I differential gear to the V- belt type CVU (Continuously Variable Unit), as an input coupled type. With the designed compound CVT, we carried out theoretical analysis and performance experiments. We proved that the compound CVT had a better performance than either of the power circulation mode or power split mode.

• 한국공작기계학회논문집
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• 제14권4호
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• pp.96-103
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• 2005

We designed the compound CVT(Continuously Variable Transmissions) by combining power circulation mode and power split mode, which have been proposed for connecting 2K-H I differential gear to the V- belt type CVU(Continuously Variable Unit), as an input coupled type. With the designed compound CVT, we carried out theoretical analysis and performance experiments for efficiency, speed ratio, power flow, and power transmission ratio. We proved that the compound CVT had a better performance than either of the power circulation mode or power split mode.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.670-673
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• 2005

We designed the compound CVT (Continuously Variable Transmissions) by combining power circulation mode CVT and power split mode CVT, which have been proposed for connecting 2K-H II differential gear to the V- belt type CVU (Continuously Variable Unit), as an input coupled type. With the designed compound CVT, we carried out theoretical analysis and performance experiments. We proved that the compound CVT had a better performance than either of the power circulation mode or power split mode.