Before the thrust needle roller bearing is completely destroyed, it provides users with enough discovery time. Don’t ignore the existence of this friction. It will reduce the speed of riding, increase the consumption of physical strength over a long distance and slow down the speed.
Causes of Damage of Timken Thrust Needle Roller Bearing and Its Maintenance Skills
If the roughness of the surface is slight and the lubricating oil film has an appropriate thickness, the probability of surface stress generation is quite low, which is why it is necessary to properly select the appropriate engine oil for lubrication.
However, if the pressure load exceeds the Pu value of the oil film (fatigue load limit value, such as too high speed and too high pressure impact), the fatigue of the material will come sooner or later.Causes of Damage of Timken Thrust Needle Roller Bearing and Its Maintenance Skills
In order to make Timken bearing clamp the axis and prevent shaft sleeve friction (this phenomenon will produce high temperature in a moment on the high-speed rotating machinery, causing the lubricating oil to burn dry and even lead to heat rise and jamming, resulting in shutdown), the inner bell and outer bowl (also known as bearing box in industry) of the bearing use a kind of “interference” phenomenon. Generally speaking, the shaft is larger than the inner bell, or the outer bowl is larger than the load, This interference requires a lot of force to install, and such installation requires a lot of force to knock Peilin, which will cause damage to Peilin in the process of knocking.
Therefore, large Timken bearings in industry usually adopt heating, hydraulic jacking and other methods.Causes of Damage of Timken Thrust Needle Roller Bearing and Its Maintenance Skills
(1) The difficulty of forming alloy in metallurgy.Causes of Damage of Timken Thrust Needle Roller Bearing and Its Maintenance Skills
(2) Affinity between material and lubricant.Causes of Damage of Timken Thrust Needle Roller Bearing and Its Maintenance Skills
(3) The friction coefficient of the paired material under the condition of no lubrication.
(4) Microstructure of materials.
(5) Thermal conductivity of the material.Causes of Damage of Timken Thrust Needle Roller Bearing and Its Maintenance Skills
(6) The surface energy of the material and the characteristics of the oxide film.
Use the oil pump to inject the high-pressure oil into the Timken bearing through the nozzle, and the oil injected into the thrust needle roller bearing flows into the oil groove through the other end of the bearing. When the bearing rotates at a high speed, the rolling element and cage also form airflow in the surrounding air at a fairly high rotation speed.
It is difficult to send the lubricating oil to the thrust needle roller bearing by general lubrication method. At this time, the lubricating oil must be sprayed into the double row deep groove ball bearing by high-pressure injection method, and the position of the nozzle should be placed between the inner ring and the center of the cage.Causes of Damage of Timken Thrust Needle Roller Bearing and Its Maintenance Skills
The clearance of needle roller bearing is divided into radial clearance and axial clearance. Its function is to ensure the normal operation and lubrication of the rolling element and moderate compensation for the internal changes of the bearing caused by thermal elongation during use.Causes of Damage of Timken Thrust Needle Roller Bearing and Its Maintenance Skills
During the assembly of needle roller bearing, the radial and axial clearance shall be adjusted to compensate for the thermal impact of the shaft when the temperature rises, so as to ensure the normal operation of the bearing. If the clearance is too small, it will make the bearing difficult to rotate, heat, and even make the rolling element stuck and damaged; If the clearance is too large, it will lead to noise, serious vibration, cage damage and direct bearing failure.
Incorrect coupling installation:Causes of Damage of Timken Thrust Needle Roller Bearing and Its Maintenance Skills
The input shaft of most operating equipment is connected with the power shaft through the coupling, so the alignment of the coupling must be carried out during assembly to make the driving shaft and the driven shaft on the same axis.
If the amount of grease is too large, the friction torque will increase, the temperature will increase, and the grease consumption will increase; If the amount of grease is too small, reliable lubrication cannot be obtained and dry friction occurs. Generally speaking, the appropriate amount of grease is 1 / 3 ~ 1 / 2 of the total void volume in the bearing. However, according to the actual situation, sometimes the bearing edge should be greased and cavity lubrication should be implemented.
Avoid the cross use of grease containers and tools, otherwise it will have adverse effects on grease, such as drop point drop, cone penetration increase and mechanical stability decrease.Main Functions of Lubricant
As the variety and quality of lubricating grease are constantly improving and changing, when the old equipment changes to new lubricating grease, it should be tested first and can be officially used after trial;
When replacing with new grease, first remove the waste grease and clean the components. When adding lubricating grease, the waste lubricating grease shall be squeezed out until new lubricating grease is seen at the grease discharge port.
Lubricating grease can reduce mechanical friction bearing, prevent metal aging and prevent air leakage, oil leakage and water leakage, so as to ensure the normal operation of mechanical equipment. When selecting lubricating oil, the following factors should be considered:Main Functions of LubricantsMain Functions of LubricantsMain Functions of Lubricants
Temperature: the temperature has a great influence on the grease. If the environment and mechanical operation temperature are high, the grease with high temperature resistance shall be selected.
Speed: the temperature rise of high-speed parts is high and fast, which is easy to dilute and lose the lubricating grease. The lubricating grease with high consistency should be selected.
Load: since the cone penetration of grease is related to the load that can be borne during use, the grease with small cone penetration (high consistency) should be selected for heavy load; If it bears both heavy load and impact load, the grease containing extreme pressure additives shall be selected, such as the grease containing molybdenum disulfide.
Requirements for special parts: selected according to different mechanical working environment. Grease with strong water resistance shall be selected in humid environment; In the dusty environment, use thick lubricating grease containing graphite; In acid containing environment, warp base grease is selected; If there are special requirements for sealing, barium based grease shall be selected.Main Functions of Lubricants
Lubricating with grease is an effective measure to improve the antifriction and anti-wear performance of moving parts of construction machinery. Due to the particularity of the service environment of construction machinery, its service life is greatly affected and the service performance of the whole machine is seriously affected. Therefore, only by recognizing the failure mechanism of lubricating grease can it be used correctly.