• International journal of advanced smart convergence
• /
• 제12권4호
• /
• pp.451-457
• /
• 2023

Global warming is causing abnormal climates such as floods, droughts, and typhoons all over the world. According to some scientists, carbon dioxide emitted from automobiles is the main cause of global warming. To cope with this, each country is making efforts to replace the existing fossil fuel-powered engine-driven cars with electric vehicles. In order to commercialize small electric vehicles in Korea, it is necessary to solve many problems such as improvement of hill climbing capacity and improvement of power performance. In this study, we propose a proprietary model for a continuously variable transmission(CVT) of a small electric vehicle that can be operated on hills, in which a spring is mounted on a driving pulley and a driven pulley. A prototype of the CVT model using a spring was manufactured and attached to a small electric vehicle body.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 춘계학술대회논문집C
• /
• pp.476-481
• /
• 2001

In a vacuum circuit breaker mechanism, a spring-actuated linkage system is used to satisfy the desired opening and closing characteristics of electric contacts. Because the opening dynamics of electric contacts is determined by such a linkage system, the stiffness, free length and attachment points of a spring become the important design parameters. In this paper, based on the energy conservation that the total system energy is constant throughout the operating range of a mechanism, a systematic design procedure of determining the spring design parameters is presented. The proposed procedure is applied to the design of an opening spring for satisfying the specified opening characteristics.

• International journal of advanced smart convergence
• /
• 제10권4호
• /
• pp.256-262
• /
• 2021

In order for small electric vehicles to drive on hilly roads in Korea, methods to improve the climbing ability and power performance of vehicles should be taken. In order to improve the power performance of small electric vehicles, the performance of motors mounted on electric vehicles should be improved. However, if the performance of the motor is improved to improve the power performance of the electric vehicle, it is possible to lower the price competitiveness accordingly. In addition, the power consumption of the battery is rapidly increased to drive the high-performance motor, so in order to introduce the small electric vehicle into the domestic market, various problems must be overcome. In order to commercialize small electric vehicles that do not emit harmful exhaust gases to the human body in the hilly domestic terrain, it is effective to introduce a separate continuously variable transmission system that can improve the climbing ability and power transmission ability. In this study, we propose a proprietary model of continuously variable transmissions that can be applied to small electric vehicles. The proposed continuously variable transmission is equipped with a spring in the driving pulley and the driven pulley, and has the advantage of performing a shift that increases torque in a situation where the vehicle needs to increase torque when driving on a hill. In addition, the basic design for commercialization of the proposed continuously variable transmission was carried out, and the prototype manufactured and attached to the body of a small electric vehicle.

• 동력기계공학회지
• /
• 제7권4호
• /
• pp.61-66
• /
• 2003

In this paper, the relation between displacement of piezoelectric material and electric field was proposed. FEA was introduced to predict the displacement and reaction force of plate spring attached in the piezoelectric material. The relation between displacement of piezoelectric material forced by plate spring and applied electric field were further verified by experimental investigation. Also, the flow rate of gas in piezoelectric valve was examined by experiment. Finally, the relation between electric field and gas flow was derived. Based on these results, these relations can be used in the design of mass flow controller.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 추계학술대회논문집A
• /
• pp.859-864
• /
• 2001

In a vacuum circuit breaker mechanism, a spring-actuated linkage system is used to satisfy the desired opening and closing characteristics of electric contacts. Because the opening and the closing dynamics of electric contacts is determined by such a linkage system, the stiffness, free length and attachment points of a spring become the important design parameters. In this paper, based on the dynamic model of the circuit breaker using a multibody dynamic program ADAMS, a optimal design procedure of determining the spring design parameters is presented. The proposed procedure is applied to the design of an opening spring for satisfying the specified opening characteristics.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2000년도 추계학술대회 논문집
• /
• pp.468-475
• /
• 2000

An air spring was accepted for rail vehicle secondary suspension to reduce and absorb tile vibration and the noise. The air spring for the electric railway was developed with domestic technology, which consisted of a cord reinforced rubber bellows, a upper plate, a lower plate and a stopper rubber spring The fatigue test was conducted in laboratory by using servo hydraulic fatigue testing system to verify the durability. And to guarantee the adaptation of this air spring, the ride comfort and the air pressure variation were measured in train test on Boondang line.

• 한국수소및신에너지학회논문집
• /
• 제23권4호
• /
• pp.404-411
• /
• 2012

This research numerically analyses the effects of the damping device on the operation characteristics of a free piston linear engine. In this paper, the free piston linear engine uses spring as a damping device. The investigated parameter is spring hardness which is varied at 0.5, 1, 2.9, and 14.7 N/mm. The effects of spring hardness on the dynamic characteristic, thermodynamic characteristic and electric power of the engine are investigated. Beside, the equivalent ratio is also changed to provide more information for this study. The simulation results show that, by increasing spring hardness from 0.5 to 14.7 N/mm, all of parameters related to dynamic characteristic such as piston velocity, acceleration, displacement, and frequency increase accordingly. Beside, the peak pressure in the cylinder and electric power are also increased when increasing spring hardness. The tendency is also observed at varied equivalent ratios.

• International journal of advanced smart convergence
• /
• 제11권3호
• /
• pp.222-228
• /
• 2022

As a means to cope with the climate change crisis caused by global warming, automobile manufacturers continue to make efforts to use the driving energy of vehicles as electricity. As a result, parts industry such as battery, motor, and controller are attracting attention. China is often seen in large cities, with electric vehicles such as electric bicycles, electric motorcycles, and small electric vehicles popularized and commercialized, mainly in large cities. However, small electric vehicles are not popular in Korea, which is why the country's topography is high in hills. In order to drive the hilly domestic roads, power performance including vehicle climbing ability should be improved. In order to improve the power performance and the climbing capacity of small electric vehicles, the capacity of the motor should be increased. However, when the performance of the motor is improved, the weight of the motor becomes heavy and the price competitiveness is likely to decrease. In addition, in order to operate a high-performance motor, the power consumption of the battery is rapidly increased, so various problems must be solved. In order to commercialize a small electric vehicle for one or two people who do not emit harmful exhaust gas to the human body in a hilly domestic terrain, it is effective to have a separate transmission system. In this study, we were conducted dynamometer test to produce a continuously variable transmission(CVT) system prototype using a spring that can be applied to a small electric vehicle and to install a CVT system prototype manufactured in a small electric vehicle. The dynamometer test results showed that the maximum speed performance, acceleration performance, and climbing performance were improved.

• 한국생산제조학회지
• /
• 제21권1호
• /
• pp.182-189
• /
• 2012

This study suggests a dynamic design process for deciding properly design parameters of a mass-spring type Wave Energy Converter (WEC) to achieve sufficient energy conversion from wave to power generator. The WEC mechanism, in this research, consists of a rigid sprung body, a platform, suspension springs and dampers. The rigid sprung body is supported on the platform via springs and dampers and vibrates translationally in the heave direction under wave excitation. At last the resulting heave motion of the sprung body is transmitted to rotating motion of the electric generator by rack and pinion, and transmission gears. For the purpose of vibration analysis, the WEC mechanism has been simply modelled as a mass-spring-damper system under harmonic base excitation. Its maximum displacement transmissibility and steady state response can be determined by using elementary vibration theory if the harmonic ocean wave data were provided. With the vibration analysis results, the suggested dynamic design process of WEC can determine all the design parameters of the WEC mechanism, such as sprung body mass, suspension spring constant, and damping coefficient that can give sufficient relative displacement transmissibility and the associated inertia moment to drive the electric generator and transmission gears.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1998년도 하계학술대회 논문집 E
• /
• pp.1614-1616
• /
• 1998

Insulation performance of major components of prefabricated joint such as epoxy insulation unit and premolded rubber cone are guaranteed by material selection design and proper manufacturing. On the other hand insulation performance of the interfaces between the premolded rubber cone and the epoxy insulation unit and the cable insulation is maintained by keeping the premolded rubber cone to close contact with such insulation by spring. Electric characteristics of a interface depend on the contact pressure, but the required characteristics are assured so far as a proper contact pressure is maintained. In this report, the interfacial pressure by pressure sensors both in the early stage and after heating cycle were measured and the simulation by FEM program were presented. The comparison of these two results show that interfacial pressure could be controlled optimally by changing the spring length and lubricant state of the interface.