Tooth Damage Evaluation Method Of Friction Plate Under Impact Load

Friction plate is a key part of clutches,it transmits power through friction,it is also the main element of brakes,absorbing the kinetic energy through friction.Friction plate make mechanical equipment and all kinds of motor vehicles work safely and reliably,thus the friction plate is a key component widely used in brake system and transmission system.The friction plate is composed of the core plate and the friction material,its damage forms are: the friction material wear,the adhesion damage,fracture of core plate,warping deformation,burning and so on.Because of speed fluctuation of the inner hub caused by torsional vibration,friction plate is under impact collision of inner hub,the impact load causes tooth surface and the tooth root damage to the friction plate,and effects the lifetime and stability of friction plate.The paper is mainly trying to study the damage of tooth root devoted by impact load and its quantitative evaluation method.The main research work includes:1)A three-dimensional model of the inner hub and friction plate were set up.MSC Adams software were used to build their multi-body dynamics model later,through dynamic analysis,the impact load force of frictional plate and inner hub with different parameters,including backlash,pressure angle,module and number of teeth were obtained.Later,tooth root stress of friction plate with those different parameters were obtained using ANSYS transient analysis,Providing the basic data for the friction plate impact force control and damage analysis.2)To control tooth root stress,dynamic models and finite element models of different sizes and shapes of holes arranged on friction plate were built,through dynamic analysis and transient analysis.The influence of holes on the tooth root stress was obtained,providing a new way to control the stress of friction plate.3)To evaluate the damage of friction plate quantitatively,a non-linear damage evaluation method which accumulate stress cycles with amplitude larger than the threshold value was proposed,lifetime of friction plate with different parameters and different sizes and shapes of holes were calculated,laid the theoretical foundation for the evaluation of friction damage.4)Aimed at the effectiveness reliability of the damage evaluation method,high-speed photography system was used to study the dynamic impact process between the friction plate and the inner hub,dynamic impact characteristics was obtained;Dynamic strain test method was used to measure the dynamic tooth root stress;Three-dimensional super depth microscopic system was used to check the fatigue failure condition of friction plate.Test results validate the accuracy of the tooth root stress calculation method and reliability of the damage evaluation method.