The invention relates to an automobile
constant speed driving shaft. The automobile
constant speed driving shaft comprises a
left half axle and a right half axle, wherein the left end of the
left half axle is assembled with a left side wheel through a
left half axle fixed knot, the right end of the left half axle is assembled with a left side half axle gear of a differential mechanism in a
power transmission device through a left half axle moving knot, the left end of the right half axle is assembled with a right side half axle gear of the differential mechanism in the
power transmission device through a right half axle moving knot, the right end of the right half axle is assembled with a right side wheel through a right half axle fixed knot, the right half axle is of a hollow axle
tube structure, the left half axle is of a
solid rod axle structure, the length of the right half axle hollow axle tube is X, the length of the left half axle
solid rod axle is Y, X is greater than Y, the torsion rigidity of the right half axle is K right, the torsion rigidity of the left half axle is K left, and the K right is equal to the K left. The automobile
constant speed driving shaft not only solves the off-tracking problem during dynamic load acceleration running of the whole vehicle caused by inconsistent torsion angles of the left half axle and the right half axle, but also eliminates
resonance phenomenon caused by different rotating speed working conditions of the engine, so that the NVH (
Noise Vibration and
Harshness) performances and economical performance of the vehicle are improved.