• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.2
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• pp.557-566
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• 1991

The metal V-belt behavior of a continuously variable transmission was investigated analytically and experimentally. Numerical results showed that nondimensional belt radial displacement increased in the radial inward direction for the driven pulley, while that of the driver pulley increased for the first 90 degrees of the active are and decreased with the increasing torque load. Experimental results for the belt radial displacement were in good agreement with the theoretical results. However, the absolute magnitude of the belt radial displacement was so small that the change in the belt displacement could not be measured in the experimental range except for the inlet region of the driven pulley, where the radial inward displacement was observed due to the effect of bending moment. The speed ratio-axial force relationship derived from the belt behavior analysis also showed god agreement with the experiment.

• Journal of Biosystems Engineering
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• v.21 no.2
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• pp.134-145
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• 1996

Since the skid-steer loader is able to work for excavating, lifting and transporting load even at the narrow space, they are widely used in the regular farm and the livestock farm. The skid-steer loader normally adopts the hydrostatic transmission because the power to move the machine backward and forward should be delivered independently on both sides of wheels. Contrast to the mechanical system such as chain and belt transmissions, however, the hydrostatic transmission is less efficient in the use of energy and more difficult in the maintenance. This study was intended to investigate the feasibility of using triangular-type belt clutch and V-belt transmission for the newly developed skid-steer loader in order to overcome the problems stated in the hydrostatic transmission. In the developed triangular-type belt clutch, the centers of driving, driven and idler sheaves are arranged in the triangular shape in a plane, and V-belts were loaded loosely on three sheaves. The power is transmitted by pressing the idler connected to a lever on the loosened V-belt. Contrast to the normal belt clutch using two sheaves, the newly developed belt clutch has the characteristics of small contact-angle of the driving sheave at no bucket load and increasing contact-angle at the time of power transmission. The results of research can be summarized as follows: 1) The developed triangular-type belt clutch adopted a spring-loaded slackside idler which could transmit more power than a fixed idler could by sacrificing the belt life. The life of V-belt used in the power transmission reached at 500 hours(6 months) when the engine power of 11.8 ㎾ was transmitted. Also, it was feasible to develop the large industrial skid-loader with the V-belt transmission by using the proper set of sheaves. 2) The developed skid-steer loader changed the rotating radius and speed with bucket loads as the conventional skid steer loader did. The rotating speed was 47 deg/s at the maximum bucket load of 2.74 kN when the minimum rotating radius was 1.5m. 3) The power required in turning at the bucket load of 2.74 kN was 4 ㎾ and the slippage of V-belt was less than 1%.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.5
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• pp.847-854
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• 1989

Axial force of a V-belt CVT is investigated experimentally. The experimental results on speed ratio-torque-axial force show good agreement with the theoretical results that were obtained in the previous work. It is also found that torque capacity of the V-belt CVT increases as the axial force and the speed ratio increase. Impending slip which occurs at the maximum torque is determined via experiments for various speed ratios. Based on the impending slip region, and the theoretical curves for the speed ratio-torque-axial force relationship, an actual operating criteria for the V-belt CVT is obtained. It is suggested to use the actual operating criteria with the theoretical equations as a basic design formula for the V-belt CVT.

• Journal of the korean Society of Automotive Engineers
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• v.12 no.6
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• pp.30-39
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• 1990

The behavior of a V-belt CVT was investigated both analytically and experimentally. It was found that as the torque load increased, the belt radial displacement increased in inward radial direction for the driven pulley while the radial displacement decreased slightly and increased for the driver pulley. The relative belt displacement for the driver was negligible compared with that of the driven. The experimental results were in good accordance with the theoretical results except for the inlet and exit region of the pulley. The speed ratio-torque load-axial force relationship derived from the belt behavior analysis also showed good agreement with the experiment. It is suggested that the results of this paper can be used as basic design informations of a V-belt CVT.

• Journal of Biosystems Engineering
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• v.24 no.2
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• pp.99-106
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• 1999

This study was conducted to provide a direction for improving the performance of triangular-type belt clutch. The power transmission characteristics and the wear of belt were investigated for two types of pulley set theoretically and experimentally. The results of research were summarized as follows: 1) Based on the theoretical analysis for the life time of belt, the wear of belt could be reduced by increasing the sizes of driving V-pulley and tension pulley, and by decreasing the tension on V-belt. 2) The pulley set # 2 could transmit more power than the pulley set # 1 could at the same slop rate. While the slip rate was 2.36% on the pulley set # 2 at the maximum power transmission, the slip rate on the pulley set # 1 was increased up to 12.2% at the same condition. 3) From the 16 hours' fatigue test, the wear of belt used n the pulley set # 1 was observed severer than that in the pulley set#2. Also, it was found that the tensile strength of belt used in the pulley set # 2 was greater than that of belt used in the pulley set # 1.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.822-825
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• 2004

Continuously variable transmission (CVT) mechanisms considered here is a V-belt drive with two variable-diameter pulleys and effective diameters. One pulley was set by a mechanical link while the other was spring-loaded to provide automatic correspondence. The center distance between the two variable-diameter pulleys was fixed. Experimental studies were executed to analyze efficiencies as change of its speed ratio.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.2
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• pp.349-357
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• 1990

Power transmission characteristics and speed ratio-torque load-axial force relationship for a metal V-belt CVT were investigated theoretically and experimentally. In the metal V-belt CVT drive, it was found that the power was transmitted by thrust force and that band tension should be greater than compression force between the metal blocks. The experimental results for the speed ratio-torque load-axial force relationship showed good agreement with those predicted using equations developed from theoretical considerations.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.6
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• pp.209-218
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• 2002

A V belt pulley is widely used in automotive industry. More than tow pulleys in one automobile are used, such items as crankshaft, water pump, air-con compressor and power steering pump. Although the shape and usage of pulleys are very simple, the design evaluation of a pulley design is difficult because the load conditions and the installation environment are complicated. So, we formulated the design evaluation for the V belt pulley by using CAE system, which enables to develop a design automation system. By using this system, an engineer can evaluate a pulley design easily without any painstaking effort, such as consideration of the complicated loads and CAE activities. Also the system helps to accumulate the design experience of a company, which guides the optimum design based on experience.

• Journal of the korean Society of Automotive Engineers
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• v.11 no.6
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• pp.68-79
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• 1989

Dynamic characteristics for an automotive V-belt CVT with centrifugal and torque-ramp actuators was investigated by bondgraph modeling method. Ten(10) state space equations for the V-belt CVT were developed from the constructed bondgraph model and linearized for perturbation at steady state. As simulation results, speed ratio versus time curves were obtained. It was found that as the ratio of the moment of inertia of the pulleys increased, the stability of the V-belt CVT system decreased. Change in the ratio of the spring constants caused the magnitude of the change of the speed ratio, but had little effect on the settling time of the system became faster and the stability of the system improved. However, the sensitivity of the speed ratio decreased with the increasing .betha.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.799-802
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• 2002

Continuously variable transmission(CVT) mechanisms considered here combine the functions of a K-H-V type differential gear unit and a V-belt type continuously variable unit(CVU). As combining the functions of a K-H-V type differential gear unit and a V-belt type CVU, 24 different mechanisms are presented. Some useful theoretical formula related to speed ratio, power flow and efficiency are derived and analyzed. These mechanisms have 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.