Yog vim li cas rau qhov hnyav hnyav ntawm lub qhov (socket) yog raws li hauv qab no:
(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) Tiv thaiv kev qaug zog
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) Abrasive hnav
Vim hais tias cov saw inevitably los rau hauv kev sib cuag nrog pulverized thee, muaj ib tug me me ntawm pulverized thee rau nws, uas yog coj mus rau qhov chaw ntawm lub sprocket saw socket. Cov thee pulverized muaj cov xuab zeb ntse me ntsis, uas yuav ua rau cov khoom nto ntawm sprocket poob tawm thaum lub sij hawm kev sib txhuam. Qhov no yog abrasive hnav. Abrasive hnav yog cuam tshuam nrog hardness ntawm cov khoom sib txhuam thiab hardness ntawm abrasive. Los ntawm daim duab ntawm kev cuam tshuam ntawm abrasive hardness ntawm hnav, nws tuaj yeem pom tias thaum lub hardness ntawm abrasive yog ze rau qhov tawv ntawm cov khoom sib txhuam, nws yuav ua rau siab - ceev hnav ntawm cov khoom sib txhuam. Vim hais tias cov hmoov coal yog tov nrog me ntsis ntse xuab zeb, qhov no kuj yog ib qho ntawm cov laj thawj tseem ceeb rau kev ua kom nrawm ntawm cov sprocket.
