Web rotary press cylinder bearing disassembly and maintenance

The maintenance of bearing parts is a vital part of the maintenance work on web rotary printing equipment. Take the Shanghai GOSS rotary printing press as an example and analyse the maintenance measures for its bearing components.

  1. Analysis of the bearing components of the Shanghai GOSS rotary printing press

In the printing unit of a Shanghai GOSS rotary press, the main components are the ink supply system and water supply system, the overprinting system, the automatic plate loading system and the printing pressure. There are many bearing components involved, with spherical roller bearings used at both ends of the cylinder. The spherical roller bearings are used at both ends of the cylinders and are controlled by a combination of clutch lever and eccentric sleeve, which enables the entire rotary printing press to be pressed off and on. With the continuous operation of the equipment, various bearing parts are susceptible to erosion by cleaning fluids and lubrication after a long period of work, resulting in various problems, such as inner ring grinding journals, which affect the normal work and printing of the rotary printing press. Therefore, in the actual operation of the rotary printing machine, it is necessary to do a good job of maintaining the various shaft components.

  1. Maintenance of GOSS rotary printing machine bearing components

2.1 Preparation before maintenance

Before maintenance, the corresponding preparations need to be made. Have all the necessary maintenance tools available, including open-end spanners and special pull codes, as well as manual hydraulic pumps and hexagonal spanners. And stop the electricity and turn off the gas.

2.2 Dismantling the bearings

The roller bearing, when dismantling the bearing, is first fitted with a connector at the end of the shaft. Then using the hydraulic pump, withdraw the bearing. Work quickly in the process of pressurisation, keeping the pressure at around 45 to 50Mpa. After separating the inner ring of the bearing and the journal, stop pressurising so that the hydraulic oil in the cylinder is not pressed out. Remove the hydraulic joint and take out the bearing and other parts related to the bearing. The bearing bores in the wall plate etc. are ground and cleaned and the journals are carefully inspected for the presence of wear. If there is no wear, the journals are cleaned thoroughly and then lubricated with a suitable amount of oil. If there is wear on the journals, the drum is lifted and the journals are machined and repaired to the exact degree of wear.

2.3 Mounting the bearings

The spherical roller bearings used in GOSS rotary printing machines have tapered bores that can withstand different forces in the radial and axial directions and are aligned to compensate for circumferential errors in order to change the bearing clearance. Because the actual maintenance process, different batches of bearings in the accuracy and clearance level there are certain differences, so, before maintenance, first need to accurately measure the reference data. Measurements are taken twice, and then, the two measurements are compared. If the data from both times remain the same, the clearance size of the bearing meets the requirements and the washer thickness is appropriate. If the benchmark data is greater than the second data, it means that the clearance is large and the washer is thin. At this point, it is necessary to thicken the washer according to the specific difference. The gaskets are then installed after adding or subtracting the corresponding shims according to the specific difference. If the reference data is less than the second data, it means that the clearance is small and the gasket is thick. In this case, the washers are thinned according to the specific difference. After grinding off the corresponding thickness on the grinding machine, the installation is carried out again.

2.4 Assembly of spindle and gear

In this case, the GOSS rotary press uses a shaft drive system with two different units connected by different drive shafts. As a result, if the gears wear out, this can affect the speed between the printing units and lead to transmission failures. In this case, it is necessary to reassemble the spindle and gears and to repair the worn parts. When reassembling, the gearbox is first dismantled and inspected, then the drive shafts are removed and the gearbox is opened to find the specific areas of wear. A repair plan is drawn up to treat the worn parts in accordance with the actual situation, and then the exact temperature of the assembly is calculated. The addition temperature is calibrated and the gear assembly is started after making sure it is accurate. The gears are heated and, once heated, they are removed and set on the shaft in the position required for assembly. The gears are then mounted in the assembly position under pressure. After cooling, the gearbox and various peripheral equipment are installed.

  1. Conclusion

For all newspaper and booklet printing enterprises, the stable and normal operation of the rotary printing press is of paramount importance. Therefore, on a daily basis, attention should be paid to the maintenance of the bearing parts of the paper rotary press, regular inspections, timely detection of problems and maintenance to ensure the smooth running of daily printing production.

Leave a Reply

Your email address will not be published. Required fields are marked *