continuously variable transmission research paper

In addition, some scholars also use noncircular gear transmission in continuously variable transmission and have achieved some good results. In these gear trains, noncircular gears have been used to account for the apparent irregular motion of the planets. Detailed descriptions of the gear trains for tracking the motions of the Mercury planet and of the Moon are herein presented by Addomine et al. put forward that the gear-shifting process structure using a noncircular gear drive instead of a friction drive. Emura and Arakawa utilized a noncircular gear for steering mechanism analysis.

Recently, the transmission technology of noncircular gear pairs has entered a new practical period. Many scholars have done a lot of research on the transmission technology of noncircular gears to solve many problems gradually, such as the geometric design of pitch curves, and the configuration and processing of gear teeth. With the development of the design and manufacturing technology of noncircular gear, combined with the characteristics of noncircular gear transmission with non-uniform speed ratio, which belongs to conjugate meshing transmission, continuously variable transmission can be realized by using the transmission characteristics of noncircular gear, which is expected to improve the power and torque transmitted. Despite these advantages, their limited torque capacity and low transmission efficiency cannot be ignored. Among them, belt CVT and chain CVT are the most common CVTs used in vehicles due to their simple structure, small size, and lightweight. įurthermore, the transmission mechanism of mechanical CVT mainly includes belt transmission, chain transmission, and gear transmission. Different from the liquid transmission mode with a higher sliding rate, and the electric transmission mode with lower efficiency and unstable operation at low speed, in this respect, mechanical continuously variable transmission can easily realize effective transmission under special work conditions, such as high load, due to the equipment of more compact structure. Generally, three main transmission modes can be adopted to realize infinitely variable speeds, namely, liquid transmission, electric transmission, and mechanical transmission. Finally, an indirect method to verify the contact ratio by detecting the contact length error of the tooth profile was proposed.Īlthough continuously variable transmission (CVT) technology has been used in vehicles for only several decades, its advantages over traditional transmission are obvious: it has a wider range of working speed ratio and it is easier to form an ideal match with the engine, so as to improve the combustion process, and further reduce fuel consumption and emissions it has higher transmission efficiency, less power loss, and higher economy. Furthermore, the accurate value of the contact tooth length was calculated based on the gear principle and the characteristics of the involute tooth profile, from this the contact tooth length error was calculated by comparing the accurate value with its actual value obtained by the rolling experiment. In addition, for improving the stability and bearing capacity of gear transmission, the noncircular gear pair transmission with high contact ratio was designed. And then the influence of pitch curve parameters in the working section on which in the non-working section was also analyzed to obtain the pitch curve suitable for transmission of this gear pair. According to the required transmission ratio in the working section, the transmission ratio function in the non-working section was constructed by using a polynomial. The linear functional noncircular gear pair, whose transmission ratio is a linear function in the working section, to realize continuously variable transmission was the research object in this paper. Although the characteristics and design methods of noncircular gear pairs have been continuously studied in China, the noncircular gear CVT is still in the preliminary exploration and research stage.

The key technology of CVT with noncircular gear has been broken through some countries, and is in the stage of deep application research.

Continuously variable transmission (CVT) of noncircular gear has the technical advantages of large bearing capacity and high transmission efficiency.

Continuously variable transmission research paper