The Effects Of Groove-Textured Surfaces On Friction-Induced Squeal Noise Of Brake Disc/Pad Materials

Friction-induced vibration and noise will not only have influence on the accuracy and reliability of the friction system, it will also substantially weaken the quality of people’s life. The interface characteristic is one particularly critical factor that will affect the friction-induced vibration and noise, and at present the work that study the relation between the interface and friction-induced vibration and noise is mostly focus on the interfacial morphology such as wear debris, asperities and roughness. In recent years, surface with textured treatment has been found to improve frictional characteristic effectively, and the information in the literature concerning the relationship between friction noise and surface with textured treatment is very limited, Therefore, to carry out the experimental study concerning the relationship between surfaces with textured treatment and friction-induced vibration and noise possess an obvious innovation and provide a guideline of supression the generation of friction squeal.In this work, groove-textured surfaces having different geometrical parameters were manufactured on brake disc materials of train, on which the grooves were distributed radially at regular angle intervals. The influence of groove-textured surfaces on friction and wear properties and friction-induced vibration and noise properties was studied in ball-on-disc (ball-on-flat) and pad-on-disc (flat-on-flat) configurations, by using chromium bearing steel ball and brake pad materials of train as the counterface, respectively. The main conclusion can be shown as following:(1) Under conditions of the experimental parameters and dimension parameters of the specimens, all the groove-textured surfaces of train brake disc material have a strong influence on level of the squeal noise, which can mainly be drawn as following:In both the ball-on-flat and flat-on-flat configurations, the squeal noise level was significantly reduced with the increase of groove width. However, the squeal noise level showed reverse tendency when the groove width increased to a limited value. While for the squeal noise level of the train pad material surface with textured treatment, the squeal noise level of smooth surface was the highest during all the test time, and the squeal noise level of the 45° groove-textured surface is the lowest. The squeal noise level of the 0° groove-textured surface was between the smooth surface and the 45° textured surface; all the squeal noise level of the three configurations of friction pad specimens were reduced with the increase of groove width of the disc specimens.(2) In both the two contact configurations, the effect of the collision and the suppression of the self-excited vibration of the groove-textured surfaces of train brake disc showed some differences that in the ball-on-flat configuration the collision between the ball and the edge of the groove can effectively disturb the self-excited vibration, and the disturbances will disappear as the edges of the groove were worn. In the flat-on-flat, there were significant collisions between the pad specimen and the edges of the grooves when the pad specimen slid across the grooves of the disc specimen, The collisions between the pad specimen and the edges of the grooves during sliding can suppress the generation of high frequency components of acceleration, which can disturb the continuous self-excited vibration of the friction system and reduce the squeal noise, The edges of the grooves remained nearly unaffected despite slight wear after the test, and the persistent collisions between the pad specimen and the edges of the grooves allowed the groove-textured surface to suppress the occurrence of squeal for a long period.(3) The suppression of the self-excited vibration of the groove-textured surfaces of train brake disc showed that the existence of the groove of 45° textured surface can make the contact stress well-distributed and enlarge the area of contact stress, and then the friction system can keep steady, which consequently can suppress the generation of friction noise.