Sound of a ball spline operated at a certain linear velocity

This article deals with the sound of light or medium-preloaded ball splines operating at a certain linear velocity. Experimental results showed that the sound waveforms of the ball splines are pulse-like with ball passage period T(p), and sound peaks f(1)-f(8) and f(1)-f(7) appear in the 20 kHz range sound spectra of the light- and medium-p reloaded ball splines, respectively. A supplemental experiment showed that the main cause of the ball spline sound is the collision between the ball and the spline shaft or spline nut at the entrance of the load zone. The measured frequencies of the sound peaks nearly matched the natural radial-bending frequencies of the spline shaft or nut obtained by finite-element method (FEM). This means that the sound peaks are caused by the natural radial-bending vibrations of the spline shaft and nut. Finally, based on the experimental and FEM results, the sound-generating mechanism of the ball splines has been elucidated.