The invention discloses a steering shaft and ball frame structure for transmitting torque; the structure comprises spline shafts arranged in a spline 
pipe, the outer side wall of each spline shaft is provided with an outer spline and a first arc-shaped roller path, the inner wall of the spline 
pipe is provided with an inner spline and a second arc-shaped roller path which are matched with the spline 
pipe, and steel balls are arranged between the first arc-shaped roller path and the second arc-shaped roller path. An annular groove is formed in the position, located at the outer spline, of the outer side wall of each spline shaft, a 
steel ball retainer is arranged at the position, corresponding to the annular groove, between the spline shafts, the 
steel ball retainer comprises arc-shaped frame bodies, and the arc-shaped frame bodies are embedded in the positions, located at the first arc-shaped roller paths, of the spline shafts. Containing grooves are formed in the arc-shaped frame bodies. The steering shaft and ball frame structure has the advantages that a complex 
surface structure can be guaranteed to the maximum extent, 
assembly can be facilitated, the strength can be guaranteed, steel balls are lubricated more sufficiently, 
torque transmission is more stable, the service life is long, and the risk that the 
retainer is disengaged can be effectively prevented.