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The reason solution of the fault of the crusher drive device

Hammer crusher is often used for crushing medium hardness materials in cement, chemical industry, electric power, metallurgy and other industrial sectors.During the operation of hammer crusher, the overheating of transmission device often occurs.The transmission device is the power part of hammer crusher. Once the problem occurs, the equipment will be shut down and the production efficiency will be seriously affected.

The drive device of hammer crusher is mainly powered by explosion-proof mining motor, which is transmitted to crusher through narrow v-shaped belt through short shaft assembly equipped with small belt pulley.The device is fixed on the crusher box base by connecting cover and adjusting shaft. The belt installation position can be adjusted by adjusting shaft.

Hammer crusher shaft components are mainly composed of short shaft, two cone roller bearings, bearing block, etc.Simple structure, but in the actual assembly and use process, often failure.

Hammer crusher

1. The bearing of the transmission device is locked


When repairing the transmission device, the bearing quality of the transmission device can be judged by checking the grease by opening the bearing cover every time.If the grease discoloration occurs, and the roller and cage are found to be blue or even broken during cleaning, the cause of bearing damage shall be analyzed.Otherwise, even if the bearing is replaced, it will fail.

In many cases, a large amount of heat is generated in the running process of the bearing, which cannot be dispersed for a short time, leading to a sharp rise in the temperature of the bearing, and eventually the bearing will be locked.This phenomenon is common in equipment overhaul and production service sites.The specific reasons are as follows:

 

1) improper assembly

 

(1) assembly of bearing outer ring and bearing seat hole or bearing inner ring and shaft improper coordination.


Sometimes due to the rapid temperature rise of the bearing, the outer ring of the bearing and the bearing seat hole occurred gluing.In the process of maintenance, use gas cutting to slowly cut the bearing outer ring into several small pieces, and finally use a chisel to knock down.To its appearance of groove, after brush plating or spray re - grinding, precision to meet the requirements of use.

However, in the actual assembly process, sometimes the inner hole was not polished and its size was measured. The bearing was replaced for assembly, and the temperature rise was found to be too high after the test run.After that, the analysis of dismantling detection quantity found that the bearing seat hole had been deformed, which caused the extrusion of the outer ring of the bearing, resulting in smaller radial clearance of the bearing, uneven rotation of the rolling body, aggravating wear and generating heat.If the clearance between the inner ring of the bearing and the shaft is too large, the inner ring of the bearing will rotate with the rolling body and the shaft, and friction will cause the bearing to heat up and vibrate.

 

(2)Improper control of bearing heating temperature during assembly.


Interference fit is adopted for the matching of rolling bearing and shaft, and the bearing heater is adopted for heating during assembly. The heating temperature required by the process should be controlled at 80 ~ 100℃, and the maximum temperature should not exceed 120℃.After heating, quickly take the inner ring and install it on the shaft neck.If the temperature of the bearing heater is too high during the heating operation, it will cause tempering and decrease the hardness and accuracy, so that the bearing temperature will increase, leading to more wear and damage of the bearing.
 

(3) assembly bearing clearance adjustment improper.


When assembling the short shaft, first install the outer ring of the bearing onto the bearing seat and install it in place.Then install the inner ring of the bearing to the side near the shaft shoulder.Then spacer Ⅱ, 2 plate bearing inner ring, in turn, installed on the shaft, then the spacer I, spacer Ⅲ, transparent cover, round nut, check back cushion installed well.Check axial clearance by dial indicator, change axial clearance by adjusting circular nut.

For tapered roller bearings with adjustable clearance, the axial clearance should be adjusted well during assembly to compensate the thermal elongation of the shaft when the temperature rises, so as to ensure the normal operation of the bearing.

If the axial clearance is too small, it will easily cause bearing heating, accelerate pitting corrosion, and even cause rolling body stuck or damaged by gluing.If the axial clearance is too large, the impact force of the motion pair increases and the stiffness decreases, abnormal sound will be generated in operation, and even serious vibration or damage to the cage.

 

2) oil seal problem


Oil seal with secondary lip is used in downhole with poor environment. The secondary lip of oil seal plays a dust-proof role to prevent impurities from intruding into the lip of oil seal, so as to extend the life of oil seal.But deputy lip place often lubricate bad, friction force is bigger, cause oil to seal dry friction and damage, when installing double lip oil seal so, must fill grease between double lips.
 

3) gaps


Bearing outer ring size determined by end cover and the bearing seat seam allowance, spacer Ⅱ size decreases, and the inner ring size will be round nut adjustment, and finally compaction, bearing the axial clearance of smaller, make its operation in the process of heating.
 

4) lubrication


Bearing grease should not be too much, grease amount is too large, will increase the friction torque, bearing temperature rise;If the amount of fat is too low, the reliable lubrication cannot be obtained and dry friction occurs.Generally speaking, the proper fatliquoring amount is 1/3 ~ 1/2 of the total void volume in the bearing.Therefore, according to the use requirements, regular injection of adequate amount of grease.

 

2.Abnormal noise of transmission device


Due to poor working environment, high-speed operation of the transmission device for a long time, oil seal damage, coal and water and other impurities into the bearing, coupled with the lubrication is not timely, resulting in the rolling body rust, slight pitting corrosion.If a metal bar is placed at the bearing socket hole and the other end is placed on the ear, a distinctive noise will be heard.This time must stop the maintenance, replacement bearings.
 

3.High vibration of transmission device


When the short shaft bearing is in normal state, the machine will give out soft and even vibration sound.When the short shaft bearing due to wear clearance beyond the standard, the vibration of the machine will be increased.Stop for maintenance and replacement of bearings.Because the short shaft drive is driven by the belt, sometimes the belt's tightness is not well adjusted, which will also cause vibration of the transmission device.
 

Troubleshooting methods


(1) in the dismantling and maintenance of the transmission device, the overhaul process should be strictly implemented and operated carefully.Replacement of bearings, seals, to be carefully inspected by the quality inspector.At the same time, check the dimension of axle diameter and bearing socket hole.

(2) when replacing short shaft components, the installation size should be measured first to prevent assembly problems.

(3) during the operation of the equipment, carefully check, find fault hidden dangers, timely eliminate.Change the grease on time to ensure the transmission is in good working condition.


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