Abstract: The mechanical variable speed drives is a general purpose gearing which can accommodate the variable requirements of the process planning, mechanization of the schedule drawing ,the development of automation and the improvement of the mechanical working capabilities. The article briefly introduce the basic structure, the way of design and calculation, material and lubricate of the frication type variable speed drives, and taking them as the theory basis of the design of mechanical variable speed drives.
This design uses the ball pyramid wheel as the middle transmission component, by changing its’ working radius to realize the continuous change of the output axis. This article analyzes the working theory and the working forces of the drive wheel, ball wheel and outer ring during the transmission process. It also deduces the practical calculation formula of the ball pyramid wheel type variable speed drives, it also goes on the material calculation aim at the selection parameter. It protracts the assemble-drawing of the ball pyramid wheel type variable speed drives and the accessory-drawing of the mostly drive component. So it can express more clearly of the structure and process planning of the variable speed drives.
The variable speed drives has good structure and properties, and it can use as batch production. The most specialties: 1 wide range of variable speed;2 the constant output power;3 it can rotate positively and versedly;4 stable accuracy of speed;5 high output power;6 long life;7 simply and precise control of speed;8 easy maintain.
Keywords: CVT,friction type,ball pyramid type,design.