• International Journal of Precision Engineering and Manufacturing
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• v.3 no.3
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• pp.28-36
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• 2002

The continuously variable transmission (CVT) mechanism considered here is the output coupled type which combines the functions of a 2K-H I type differential gear unit and a V-belt type continuously variable unit (CVU). One shaft of the CVU is connected directly to the output shaft and another shaft of it is linked to the differential gear unit. It is shown that some fundamental relations (speed ratios, power flows and efficiencies) for twelve mechanisms previously described are valid by various experimental studies, six of them produce a power circulation and the others produce a power split. Parametric analysis is carried out in relation to the efficiency, speed ratio and power ratios in order to assist in the design of an optimum configuration. Some useful properties associated with power flow modes also are discussed in the output coupled type continuously variable transmission.

• Journal of Power System Engineering
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• v.17 no.1
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• pp.85-90
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• 2013

Dry CVT consists of a driving pulley and a driven pulley joined by rubber V-belt. Each pulley consists of a fixed flange and a movable flange. The movable flange moves toward a fixed flange under the actuation of a centrifugal roller, as the driving pulley speed increases. The important claim which have an influence on the performance of the Dry CVT is the wear of the centrifugal roller. In this study ball type is proposed instead of roller type of movable flange to resolve the claim. Simulation is carried out for new model to verificate performance, experiments are carried out for new model to evaluate performances.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.637-638
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• 2006

V-belt pulleys play a key role in driving cooling pump, oil pump, air-conditioner and so on by using an engine power. Precision deep drawing is one of the main processes for manufacturing the pulleys. Operation variables of the deep drawing equipment, called the setup parameter, must be re-determined whenever the specifications of pulley to be produced are changed. The defect rates during a setup of equipment and the working hours needed for the setup are almost dependent on workers' know-how. This study designs the program for easily determining setup conditions in pulley manufacturing process.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.61-64
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• 2002

In this study, It was designed and developed optimal rotary dressing system of centerless grinding using for ferrule machining. Dressing shaft's dropping is calculated by Finite Element Method, and bearing 7206ADB, 7005ADB is selected. Dressing wheel $GC\Box \;200\Box\; G\Box\; m\Box\; V-100^*25^*16$ is selected by pre-research. Also Motor, pulley, belt are selected, 0.4Kw-60Hz, 48.2 mm diameter, 2-5M-730 type, each.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.4
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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.

• Journal of Power System Engineering
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• v.10 no.4
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• pp.165-171
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• 2006

An experiment to observe reduction of pressure fluctuation in the compressing system utilizing snubber has done. The experiment measured pressure at inlet and outlet of snubber. It used an air compressor as a model of hydrogen one. Snubber with buffer and snubber without buffer were used to get comprehensive comparison between both of that snubber. An analysis by using Fast Fourier Transform (FFT) method was conducted to verify working pressure frequency. With this method pure signal of static pressure was filtered from noisy signal. The experiment was run for several speeds of piston movement. It was controlled by adjustable frequency regulator that controled rotation of actuator motor. This was connected to the piston-reciprocating compressor with V-belt. From result obtained, the fluctuation was increasing proportionally when frequency of driver motor was increased.

• Journal of Mechanical Science and Technology
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• v.20 no.6
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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.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.11
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• pp.141-150
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• 2000

Continuously variable transmission(CVT) combined differential gear unit has many advantages, which are the decrease of CVT size, the increase of overall efficiency, the extension of speed ratio range, and the generation of geared neutral. It is known that such CVT can be classified into the input coupled type and the output coupled type according to the coupling location of continuously variable unit(CVU). In this paper, six different configurations of input coupled type CVT combined V-belt CVU and 2K-H I type differential gear unit are proposed. Some useful theoretical formula related to speed ratio, power flow and efficiency are derived and analyzed. The propriety of derived formula and theoretical analysis are proven by various experiments.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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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.

• The Journal of the Petrological Society of Korea
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• v.3 no.3
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• pp.196-219
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• 1994

Granulite complexes in northern (the Nangnim block), eastern (ther Kimchaek zone of the Macheonryong belt) and southern (separate windows among upper Proterozoic structure such as the Wonsan, Nampo and Haeju granulites) parts of the Northern Korea are studied. Multistage deformations, metamorphic and migmatitic events, and granite formations are recognized in these granulite complexes. Mineral thermobarometry and fluid inclusion investigationss are used to establish the P-T evolutionary trends during prograde and retrograde metamorphic events. The peak metamorphism of granulites is characterized by temperature near $800^{\circ}C$ and pressure near 5.5-6 kb. Retrograde evolution includes cooling at constant pressure or with variable pressure ranging up to 7-8 kb. This P-T change corresponds to the transition from high to moderate or low geothermal gradient. The subsequent cooling is ac-companied by significant decompression to 3-4 kb.