The invention discloses a part knocking suppression device. A hollow cylindrical structure is arranged on an input spline, a cylindrical or conical friction pair is provided, a damping ring is connected with an output spline through an elastic element, the damping ring is formed by a plurality of sections which are in contact with each other and restrict with each other, the maximum diameter of the circle is larger than that of the cylindrical or conical friction pair on the input spline, and the outer diameter of the circle is shrunk inwards by the constraint of an input spline friction pair,so that the elastic element is pressed to generate a pre-tightening force, the pressing force acts on the friction pair of the damping ring and the input spline, a mutual friction damping is formed,and knocking caused by the tooth side clearance of the spline is avoided. The part knocking suppression device has the advantages that spline teeth are prevented from being knocked when the torque istransmitted, and the service life of parts is prolonged.