The structural characteristics and working principle of an IVT（Infinitely Variable Transmission）system with the traction transmission implemented by a pair of friction hemisphere introduced.Torque is transmitted by rolling friction which is generated through the rigid connection between the driving link and driven link.Compressed mechanism is driven by speed control mechanism to change the relative position between the pair of links

resulting in infinitely and continuously variable transmission ratio.Power is ultimately output through cross shaft universal coupling connected with the driven shaft so that it can bring about a variable power of continuous change.Using MATLAB

the curve of displacement between speed control mechanism and drive ratio is obtained

the result shows that transmission ratio continuously change within an infinite range can be realized by changing the displacement of speed control mechanism in theory.In the conclusion

this system provides a profitable reference for the further optimization and development of a new generation of IVT.