Attention points

From a usage perspective, to ensure the reliable operation of bearings, the following points should be noted:

1. Improve lubrication quality, control oil pressure, temperature, and flow rate, and strengthen oil filtration.

2. Use fuel and lubricating oil that comply with regulations.

3. Controlling the temperature state of diesel generator sets is unfavorable for operation under conditions of supercooling and overheating. In cold weather, the diesel engine should be preheated before starting, and the crankshaft should be manually rotated to allow the oil to enter the friction surface.

4. The surface quality and geometric shape of bearings and shaft necks should be strictly guaranteed.

5. The bearing clearance should be appropriate. If the generator set is too large, it will cause impact, while if it is too small, it will result in poor lubrication and may burn the bearings.

How to ensure the reliable operation of bearings? Generally speaking, from the perspective of use, the following points should be noted:

1. The bearing clearance should be appropriate. If it is too large, it will cause impact, while if it is too small, it will result in poor lubrication and may burn the bearings;

2. The surface quality and geometric shape of bearings and shaft necks should be strictly guaranteed;

3. Improve lubrication quality, control oil pressure, temperature, and flow rate, and strengthen oil filtration;

4. Use fuel and lubricating oil that comply with regulations.

In order to fully utilize and maintain the expected performance of bearings in the long term, regular maintenance and upkeep (regular inspections) must be carried out effectively. Early detection of faults and prevention of accidents through appropriate regular inspections are crucial for improving productivity and economy.

Install

The correct installation of bearings affects accuracy, lifespan, and performance. Therefore, the design and assembly department should conduct thorough research on the installation of bearings. I hope to install according to the homework standards. The items for homework standards are usually as follows:

(1) Cleaning bearings and their related components

(2) Check the dimensions and precision machining of related components

(3) Installation

(4) Inspection after installing the bearings

(5) Supply lubricant

I hope to open the bearing packaging just before installation. Generally lubricated with grease, without cleaning, directly filled with grease. Lubricating oil lubrication is not necessary for regular use, but for instrument or high-speed bearings, they should be cleaned with clean oil to remove rust inhibitors applied to the bearings. Bearings without rust inhibitors are prone to rusting, so they cannot be left unattended. Furthermore, bearings that have been sealed with grease can be used directly without cleaning.

The installation method of bearings varies depending on the bearing structure, fit, and conditions. Generally, due to the rotation of the shaft, the inner ring requires interference fit. Cylindrical bore bearings are often pressed in with a press or hot installed. In the case of a tapered hole, it can be directly installed on the tapered shaft or installed with a sleeve.

When installed on the casing, there is usually more clearance fit and interference fit on the outer ring. It is usually pressed in with a press or there is also a cold shrink fit method for installation after cooling. When using dry ice as a coolant and installing it with cold shrink fit, moisture in the air will condense on the surface of the bearing. So, appropriate rust prevention measures are needed.

Maintenance and dismantling

The disassembly of bearings is a regular maintenance and is carried out during bearing replacement. After disassembly, if it is necessary to continue using or to check the condition of the bearings, the disassembly should be carried out with the same care as during installation. Be careful not to damage the various parts of the bearing, especially the disassembly of interference fit bearings, which is difficult to operate.

It is also very important to design and manufacture disassembly tools as needed. When disassembling, study the disassembly method, sequence, and investigate the fitting conditions of the bearings according to the drawings to ensure that the disassembly operation is foolproof.

The disassembly of the outer ring with interference fit requires setting several outer ring compression screws on the circumference of the shell in advance, tightening the screws evenly while disassembling. These screw holes are usually covered with blind plugs, tapered roller bearings, and other separable bearings. Several cuts are made on the shoulder of the housing cover, and they can be disassembled using pads, a press, or gently tapped.

The disassembly of the inner ring can be easily done by pulling it out with a press. At this point, it is important to ensure that the inner ring bears its pulling force. Furthermore, the illustrated pull-out card holder is often used, and regardless of the type of card holder, it must be firmly attached to the inner ring side. For this, it is necessary to consider the size of the shaft shoulder or study the machining of grooves at the shoulder for the use of drawing fixtures.

The inner ring of large bearings is disassembled using hydraulic pressure method. By setting oil pressure in the oil hole of the bearing, it is easy to pull out. Bearings with a large width can be disassembled using both hydraulic pressure and drawing tools.

The inner ring of cylindrical roller bearings can be disassembled using induction heating method. The method of heating the local area in a short period of time to expand the inner ring and then pulling it out. In situations where a large number of such bearing inner rings need to be installed, induction heating method is also used.

Clean

When disassembling the bearing for inspection, first use photography or other methods to make a good appearance record. In addition, it is necessary to confirm the amount of remaining lubricant and sample the lubricant before cleaning the bearings.

a. The cleaning of bearings is divided into coarse cleaning and fine cleaning, and a metal mesh can be placed at the bottom of the container being used.

b. During rough cleaning, use a brush or other tool to remove lubricating grease or adhesive from the oil. If the bearing is rotated in oil at this time, be careful not to damage the rolling surface due to foreign objects or other factors.

c. When performing precision cleaning, slowly rotate the bearing in oil, and it must be done carefully.

The commonly used cleaning agents are neutral, water free diesel or kerosene, and sometimes warm alkaline solutions are also used as needed. Regardless of the type of cleaning agent used, it is important to filter regularly to maintain cleanliness.

After cleaning, immediately apply rust proof oil or grease to the bearings.

Inspection and judgment

In order to determine whether the removed bearing can be reused, it is important to focus on checking its dimensional accuracy, rotational accuracy, internal clearance, as well as mating surfaces, raceway surfaces, retainers, and sealing rings. Large bearings cannot be rotated by hand, so it is important to check the appearance of the rolling elements, raceway surfaces, retainers, and retaining surfaces. The higher the importance of bearings, the more careful the inspection must be.

Reasons and elimination methods for heating of rolling bearings

Low bearing accuracy: Choose bearings with the specified accuracy level.

Spindle bending or non concentric box holes: repair the spindle or box.

Poor lubrication: Use lubricating materials of the specified grade and clean them appropriately.

Low assembly quality: Improve assembly quality.

Inner shell running of bearings: Replace bearings and related worn parts.

Excessive axial force: Clean and adjust the gap between the sealing ring to be between 0.2-0.3mm, correct the diameter of the impeller balance hole, and verify the static balance value.

Bearing damage: Replace the bearing.

Safekeeping

The bearings are coated with an appropriate amount of anti rust oil and packaged with anti rust paper at the factory. As long as the packaging is not damaged, the quality of the bearings will be guaranteed. However, for long-term storage, it is advisable to store on a shelf 30cm above the ground under conditions of humidity below 65% and temperature around 20 ℃. In addition, the storage location should avoid direct sunlight or contact with cold walls.