In the mining sand and gravel industry, crushers are widely used, but for jaw crushers, we need to pay attention to the abnormal temperature rise of the bearings!
Before understanding the cause of the failure, let's get familiar with the installation location of the jaw crush bearing:
Two pairs of bearings are installed on the jaw crusher:
1. A pair of bearings are installed between the frame and the eccentric shaft as frame bearings. The frame bearings support the eccentric shaft for rotation.
2. The other pair is installed between the movable jaw and the eccentric shaft. It is a movable jaw bearing, which supports the movable jaw to swing when the eccentric shaft rotates.
Two pairs of bearings transfer the crushed material load to the frame when the crusher is running, and are one of the important parts of the jaw crusher.
Reasons for bearing damage:
For the jaw crusher, the role of the bearing is self-evident, once it is damaged, it is easy to cause downtime.
However, in production, various problems will inevitably occur in the bearing, and abnormal temperature rise is one of the common faults.
Today we will talk about the causes of this problem.
01. The bearing is severely worn or the cage is damaged.
Bearing wear, the inner ring, outer ring, rolling elements, cage, etc. of the bearing will undergo dimensional changes, and the running accuracy will be reduced.
It will cause the bearing temperature to rise, the vibration to increase, and the noise to increase. In severe cases, it will cause heat generation, increased vibration, bearing burnout, and even shaft bending.
02. The bearing quality is poor and the original clearance is too small.
The clearance of the bearing does not reach the specified value, which will cause the clearance to be too small after installation, which will cause the bearing to generate heat and increase the temperature during the operation of the bearing.
03. The axial positioning of the bearing is incorrect.
Once there is a problem with the axial positioning of the bearing, the labyrinth ring or the bearing gland is not installed in place.
During operation, the eccentric shaft moves on one side, which reduces the bearing clearance and causes the bearing to generate heat.
04, The machining error of the movable jaw bearing hole is large.
The machining error of the bearing hole is large, and the coaxiality exceeds the allowable value, which results in a large coaxiality error of the outer ring of the bearing after the two disc movable jaw bearings are installed, which will cause the clearance to become smaller and the bearing to heat up.
05. There is a problem with the spindle processing.
The coaxiality error of the bearing journals installed on both sides of the main shaft is too large, which exceeds the allowable value of the design.
In this way, the coaxiality error of the inner ring is too large after the bearings at both ends are installed, resulting in a smaller clearance and heating of the bearing.
06. Axial movement of the tightening bushing occurs.
At this time, the bearing cover on the frame should be disassembled, the fixed bushing should be tightened, the flywheel or sheave should be removed, and a new fixed bushing should be replaced.
07. The oil hole is blocked and the bearing is cut off.
When the amount of oil is too much, it reaches or exceeds the center of the bottom ball or roller, which does not meet the requirements of bearing lubrication, and generates too much heat during constant stirring.
The heat dissipation area of the shell is insufficient, the heat cannot be dissipated in time, cannot be balanced within the required temperature, and the bearing temperature remains high.
When the equipment is running, read the instructions carefully, and according to the provisions of the instructions, refuel on time and quantitatively.
08. The machining accuracy of the parts is not up to the requirements.
The machining accuracy of equipment parts cannot meet the requirements, especially the machining accuracy of the bearing seat cannot meet the requirements, which is also an important factor.
The machining of the bearing seat hole must ensure the tolerance, roughness and cylindricity requirements of the hole.
If the hole tolerance is too small, the bearing clearance during fitting will be too small, and if the hole tolerance is too large, the fitting will loosen. Both of these situations will cause the bearing to heat up.
09. Improper selection of lubricating oil.
Bearing lubricants should be selected according to factors such as bearing operating temperature, speed index, load characteristics, and lubrication methods.
(1) Inappropriate selection of lubricants, too low viscosity, difficult to form oil film.
(2) The viscosity is too large, which increases the internal friction between the lubricating oil molecules and also increases the friction between the lubricating oil and the metal.
10. Non-bearing heating
The frictional heat generated by the movable jaw seal sleeve and the end cover, or the double-inlaid cover of the frame bearing seat and the spindle rotates together, will be regarded as abnormal bearing temperature rise.
At this time, the end cover and sealing sleeve of the jaw crusher should be replaced, or the upper bearing cover on the heating end of the bearing housing of the frame should be loosened.
Use the fuse and the embedded cover to press into the bearing seat groove of the frame, and then fix the bearing cover to eliminate the rotation of the embedded cover.