Rezon ki fè yo mete grav nan priz piyon an se jan sa a:
(1) The greater the adhesive wear load and the higher the surface temperature, the more serious the adhesion phenomenon. For metal materials with a certain hardness, wear tests are performed under different pressures to obtain a graph of the relationship between wear rate and pressure. When the pressure reaches more than 1/3 of the hardness of the material, severe wear will occur. According to the stress distribution diagram, it can be seen that the maximum stress contact point is the maximum pressure, and its value is 884.4 MPa. Because the quenching hardness of the chain socket is HRC4852, the corresponding hardness value is 4800MPa. Therefore, the pressure is far less than 1/3 of the material's hardness, so adhesive wear is not the main form of sprocket wear.
(2) kontak fatig mete
The friction pair of the sprocket and the chain is an alternating contact stress, which is prone to fatigue pitting on the friction surface. The index for judging the contact fatigue strength of metals is the contact fatigue limit, that is, the maximum stress at which pitting corrosion does not occur under a certain number of stress cycles. The contact fatigue limit of 40Cr is σ0H=HRC17 plus 200 after surface quenching treatment, and σ0H=1016MPa is calculated. According to the stress distribution diagram, the maximum stress value of the sprocket socket is 884.4 MPa. Its value is very close to the allowable contact fatigue limit of the sprocket surface, and it is easier to cause pitting failure at the maximum stress. However, due to the poor lubrication conditions of the sprocket and the chain, pitting corrosion is too late to form and has caused wear. At this time, the main form of damage is wear rather than pitting. Contact fatigue wear is the main form of sprocket wear, which basically determines the service life of the sprocket.
(3) Mete abrazif
Paske chèn lan inevitableman antre an kontak ak chabon pulverize, gen yon ti kantite chabon pulverize sou li, ki mennen nan pwen an kontak nan priz la chèn piyon. Chabon pulverize a gen yon ti sab byen file, ki pral lakòz materyèl sifas piyon an tonbe pandan pwosesis friksyon an. Sa a se mete abrazif. Mete abrazif ki gen rapò ak dite nan materyèl la friksyon ak dite nan abrazif la. Soti nan graf la nan enfliyans nan dite abrazif sou mete, li ka wè ke lè dite nan abrazif la se tou pre dite a nan materyèl la friksyon, li pral lakòz gwo -vitès mete nan materyèl la friksyon. Paske se poud chabon an melanje ak yon ti sab byen file, sa a se tou youn nan rezon prensipal pou akselere mete nan piyon an.
