Common failure analysis of bearings in printing press

Common failure analysis of bearings in printing press

Modern multi-color offset printing press embellishment system has a middle roller digital printing press, this middle roller is ink road communication bridge! In addition to play a rapid ink balancing role, but also can remove by the version of the water roller floating ink. During the operation of the printing press, the water roller is in direct contact with the fish. Inevitably some ink float CTP will stick from its surface! These ink floats may be deposited on the surface of the water roller, affecting the hydrophilicity of the water roller, and may also be returned to the tank with the moistening solution, affecting the wettability of each color group. With this middle roller, the ink floating on the water roller can be transferred to the adjacent ink roller, so integration.

This effect on the printing effect is relatively small, but also can effectively improve production efficiency, prepress equipment imported bearings in the process of high-speed failure is often, do not make a fuss, but do a good job of fault judgment and timely treatment is the key.

1. When the bearing temperature is too high, the installation bearing part is allowed to have a certain temperature. Need to shut down the press immediately! In order to avoid greater loss of equipment, the reasons for the noise of rolling bearings are more complex. 1. The inner and outer rings of bearings match the surface wear. The mating relationship between the bearing and the shaft causes the axis to deviate from the correct position of the plate, and abnormal sound occurs when the shaft is running at high speed.

2, when the bearing operation fatigue, its surface metal spalling. It will also increase the radial clearance of bearings, produce abnormal noise, insufficient bearing lubrication, and form dry friction! Bearing breakage will produce abnormal sound, bearing wear loose tobacco packaging. Bearing cage loose and damaged. There will also be abnormal noise. Analysis of bearing failure and damage causes can help us improve our work, improve the service life of bearings, reduce the failure rate of printing equipment, raceway surface metal spalling bearing rolling body and inner and outer raceway surface are under periodic pulsating load acquisition, resulting in periodic change of contact stress. Lubricating oil quality does not meet the requirements or deterioration, and bearing assembly is too tight.

3. Uneven pits appear on the contact surface between the raceway and the roller of the plastic deformation bearing. That the bearing produces plastic deformation! The reason is that the local stress on the working surface of the bearing exceeds the yield limit of the material under the action of great static load or impact load. This usually happens on low speed rotating bearings!

4, bearing ring crack Bearing ring crack may be caused by the bearing match is too tight. The bearing foreign or inner ring is loose, the bearing inclusion part is deformed, and the mounting bearing surface is not processed properly.

5. The reason for the fracture of the bearing cage is insufficient lubrication. Rolling body broken, seat ring skew, etc.

6. The possible reason for the cage metal adhesion on the rolling body is that the rolling body is stuck in the cage or has insufficient lubrication.

7. Serious wear of the raceway of the seat ring may be caused by foreign body Roland in the seat ring, insufficient lubricating oil or improper lubricating oil grade. Why should we pay attention to imported bearing lubrication packaging containers in daily use?

Many people do not pay attention to imported bearing lubrication, they think that lubrication has little impact on bearings, but make the bearing rolling contact surface form an appropriate oil film, prolong the bearing fatigue life, packaging and decoration he causes heat, 4 through lubrication can achieve rust and dust prevention on bearings! Therefore, we should correctly understand the importance of lubrication for bearing flexographic printing. Improve the service life of bearings and reduce the failure rate of printing equipment. Or the rivet loosens significantly. Due to heat caused by obvious discoloration, carton carton bearing.

Mounting method of printing press bearings

How should the printing press bearings be installed? The pressure should be directly applied to the end face of the closely matched ring, and the pressure should not be transferred through the rolling body. The following methods are generally adopted:

The bearing outer ring is closely matched with the bearing seat hole, and when the inner ring is loosely matched with the shaft, the bearing can be pressed into the bearing seat hole first, and the outer diameter of the assembly sleeve should be slightly less than the diameter of the seat hole.

If the bearing ring is tightly fitted with the shaft and seat hole, the inner ring and outer ring should be pressed into the shaft and seat hole at the same time, and the structure of the assembly sleeve should be able to hold the end face of the inner ring and outer ring of the bearing at the same time.

1. Heating match

By heating the bearing or bearing seat, using thermal expansion to change the tight fit into a loose fit installation method. It is a common and labor-saving installation method. This method is suitable for the installation of bearings with large interference amount. Before hot loading, put the rings of bearings or separable bearings into the oil tank for uniform heating of 80-100℃, and then take them out of the oil and install them on the shaft as soon as possible. In order to prevent the inner ring end face and shaft shoulder from fitting tightly after cooling, the bearings can be tightened axially after cooling. When the bearing outer ring is closely matched with the bearing seat made of light metal, the hot loading method of heating the bearing seat can avoid the abrasion of the mating surface.

When heating the bearing with the tank, there should be a grid at a certain distance from the bottom of the tank, or the bearing should be hung with hooks. The bearing should not be placed on the bottom of the tank to prevent impurities from entering the bearing or uneven heating. There must be a thermometer in the tank to strictly control the oil temperature not exceeding 100℃ to prevent the tempering effect and reduce the hardness of the ring.

2, about the installation of thrust bearing

The comprehensive coordination of thrust bearing and shaft is generally transition coordination, and the coordination of seat ring and bearing seat hole is generally clearance coordination, so this kind of bearing is easier to install. The central shaft spring of two-way thrust bearing should be fixed on the shaft to prevent rotation relative to the shaft.

The installation method of bearings is generally that the shaft rotates most, so the match between the inner ring and the shaft is an over-win match, and the match between the bearing outer ring and the bearing chamber is a clearance match.

1) Bearing preparation

As bearings are treated with rust prevention and packaged, do not open the package until installation.

In addition, the bearing coated with antirust oil has good lubrication performance, for general purpose bearings or bearings filled with grease, can be used directly without cleaning. But for instrument bearings or bearings used for high-speed rotation, clean cleaning oil will be used to wash the anti-rust oil, then the bearing is easy to rust, can not be placed for a long time.

2) Inspection of shaft and shell

Clean bearings and housing to make sure there are no scars or burrs left by machining. The shell must not have abrasive (SiC, Al2O3, etc.) sand, chips, etc.

Secondly, check whether the size, shape and processing quality of the shaft and the shell are in line with the drawings.

Before mounting the bearing, apply mechanical oil to the mating surfaces of the inspected shaft and housing.

Interference fit and clearance fit can be used for inner ring and outer ring respectively, because of axial rotation in general, and when the outer ring is rotating, the outer ring will use interference fit.

(1) Press into the installation

Press installation is generally used, but also bolts and nuts can be used, if necessary, can be used to hammer into the installation.

(2) Hot sleeve installation

The hot sleeve method of heating the bearing in oil to expand it and then installing it on the shaft can make the bearing avoid unnecessary external force and complete the installation work in a short time.

3. Heating precautions:

1) Generally, the heating should not exceed 100 degrees Celsius.

2) The bearing is not allowed to contact the bottom of the oil groove.

In addition, the hot sleeve installation can also use the induction heating device to heat the bearing to expand it and then install it on the shaft.