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Electric motorcycles are widely used in developing countries due to they have some advantages of electric vehicles such as not using Petro-fuel, saving operating costs, and so on. Especially, they might suitable to drive in small streets and alleyways in some developing country cities. In addition, the use of electric power sources could contribute to decrease the pollution caused by exhaust emission from vehicles using gasoline fuel leading to the environmental protection. Therefore, development the electric motorcycles might be a sustainable direction for transportation system and is interested in many developing countries around the world. Unfortunately, most types of electric motorcycles recently do not integrate a Continuously Variable Transmission (CVT) into the drive system. This could lead to the problem that they might not ensure a suitable torque at low speeds, especially when traveling in the special traffic conditions in urban areas. This paper presents a design of a drive system including a CVT transmission integrated into a Cygnus motorcycle frame to develop an electric motorcycle with the goal of safe operation, avoiding the phenomenon of sliding and jerking when the speed changes. The results showed that electric motorcycles can operate stably with a maximum speed of 30 km/h, traveling distance about 57 km for each single charge, without jerkiness phenomenon when accelerating or deceleration as common electric motorcycles in the market.

In surface finishing of a grinding machine, the dimension accuracy of the workpiece is most affected by the stiffness of the spindle. For the hydrostatic spindle of a medium-sized circular grinding machine, the primary factors affecting the oil film stiffness are bearing structure parameters, lubrication characteristics, and working conditions. In this study, the effects of lubricant pressure and oil viscosity on the stiffness of the hydrostatic spindle based on the working conditions were investigated. The oil viscosity affects the spindle by increasing the stiffness that corresponds to the increase in viscosity in the range of 0.001–0.002 Pa[Formula: see text]S, while the stiffness proportionally increases with pump pressure changing in the range of 3–5 MPa. Experimental results also indicate that based on the stiffness of the bearing, a viscosity of 0.002 Pa[Formula: see text]S, pump pressure of 5 MPa, and load range of 500–1000 N are the most feasible working conditions for hydrostatic spindle associated with the fine-machining process on a medium-sized external grinding machine.

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