Noise Reduction of Continuously Variable Transmission (CVT) for Automobile

The continuously variable transmission, CVT for automobile, which consists of the primary and secondary pulley connected by the steel belt with many thin plate elements inserted in line, is becoming popular because of efficient fuel consumption, smooth variation and acceleration. But due to engagement and disengagement between the pulley and element, a distinctive noise may be generated according to the revolution. In this paper such distinctive noise at specific frequency is confirmed using a test rig of CVT and also the Operational Deflection Shape, ODS of the belt at very limited points is measured due to difficult access of non- contact sensor in the test rig. Then the FE model of the CVT is created and updated to match the FRF calculated and measured. Based on the FE model and measured ODS at very limited points, the excitation force can be assumed during the rotation that causes the ODS and generates the noise. Finally alternative element design is proposed to reduce the distinctive noise and verified by the actual measurement.