Related knowledge of water pump bearings (1)

Update:01-07-2021
Summary:

1. Installation of rolling bearing of water pump The co […]

1. Installation of rolling bearing of water pump
The correct installation of the rolling bearing of the water pump affects the accuracy, life and performance. Therefore, the design and assembly department must fully study the installation of the rolling bearing of the water pump.
Hope to install in accordance with operating standards. The standard operation items are usually as follows:
1) Clean the rolling bearing of the water pump and the related parts of the rolling bearing of the water pump;
2) Check the dimensions and finishing conditions of related parts;
3) Installation;
4) Inspection after installing the rolling bearing of the water pump;
5) Supply lubricant;
It is hoped that the package of the rolling bearing of the water pump will be opened just before the installation. General grease lubrication, without cleaning, directly filled with grease. Lubricating oil is lubricated, and cleaning is not usually necessary. However, the rolling bearings of equipment or high-speed water pumps should be washed with clean oil to remove the anti-rust agent coated on the rolling bearings of the water pump. The rolling bearing of the water pump with the anti-rust agent removed is easy to rust, so it cannot be left alone.
In addition, the rolling bearings of the water pump that have been sealed with grease can be used directly without cleaning. The installation method of the rolling bearing of the water pump varies with the structure, fit and conditions of the rolling bearing of the water pump. Generally, since most of the shaft rotates, the inner ring needs an interference fit. Rolling bearings of cylindrical bore water pumps are usually pressed in with a press or hot-packed. In the case of a tapered hole, install it directly on the tapered shaft or install it with a sleeve.
When it is installed on the shell, there is generally a lot of clearance fit, and the outer ring has an interference. It is usually pressed in with a press, or there is also a shrink fit method for installation after cooling. When dry ice is used as the coolant, the moisture in the air will condense on the surface of the rolling bearing of the water pump when the shrink fit is installed. Therefore, appropriate anti-rust measures are required.
2. Water pump rolling bearing material
The rings and rolling elements of the rolling bearing of a rolling water pump bear high contact pressure repeatedly while making rolling contact accompanied by sliding. The cage is in sliding contact with the two sides of the ring and the rolling element or one of the sides, and the other side bears the tensile force and the compressive force. Therefore, the main requirements for the material and performance of the ring, rolling element and cage of the water pump rolling bearing are as follows:
1) The required properties of ferrule and rolling element materials: high rolling fatigue strength, high hardness, and high wear resistance;
2) The required performance of the cage material: good dimensional stability and high mechanical strength.
3) Good processability is required. Depending on the application, it is also required to have good impact resistance, heat resistance, and corrosion resistance.
Material of rings and rolling elements
Rings and rolling elements usually use high-carbon chromium water pump rolling bearing steel. Most of the water pump rolling bearings use SUJ2 in the JIS steel grade. The rolling bearings of large water pumps use SUJ3. The chemical composition of SUJ2 has been standardized as a material for water pump rolling bearings in various countries around the world.
When further impact resistance is required, chromium steel, chromium molybdenum steel, nickel chromium molybdenum steel is used as the water pump rolling bearing material, and carburizing and quenching are used to make the steel have a hardened layer from the surface to an appropriate depth. The carburizing water pump rolling bearing with proper hardening depth, fine structure, proper hardness surface and core hardness has better impact resistance than the water pump rolling bearing using water pump rolling bearing steel. The chemical composition of the general carburizing water pump rolling bearing steel . NSK and DKF have implemented vacuum degassing treatment, so the materials used have high purity, low oxygen content and good quality.
Furthermore, proper heat treatment is adopted to significantly increase the rolling fatigue life of the rolling bearing of the water pump. In addition to the above-mentioned steel grades, high-speed steel with excellent heat resistance and stainless steel with good corrosion resistance are also used for special purposes.
Cage material
The material of the stamping cage is low-carbon steel. Depending on the application, brass plates and stainless steel plates are also used. The material for cutting the cage is made of high-strength brass, carbon steel, and synthetic resin.
3. Custody of the rolling bearing of water pump
The storage of water pump rolling bearings must first fully consider the size and weight of the stored water pump rolling bearings, and secondly, consider the necessary handling space and equipment to ensure that they will not collide with the water pump rolling bearings during storage and retrieval. Do not place the rolling bearing of the water pump directly on the ground.
Therefore, it is necessary to configure a proper shelf, and the bottom of the shelf should be 30cm higher than the ground. In the general packaging state, it varies with the storage environment, and the anti-rust effect is 13 years. When storage is required for nearly 10 years under special circumstances, the storage method can be immersed in oil such as turbine oil (as lubricant for water pump rolling bearings).
(1) Installation of rolling bearing of water pump
There are many ways to install the rolling bearing of the water pump, and the same work will be done after installation. After the rolling bearing of the water pump is installed, be sure to coat the outer ring with the lubricant for the rolling bearing of the water pump.
Lubricant application
1) For grease lubrication, apply lubrication to cover all roller surfaces, and restore the position of the outer ring after the application.
2) For oil lubrication, coat all roller surfaces with oil, and restore the position of the outer ring after coating.
3) After coating, cover with plastic film to prevent dust
(2) Precautions for disassembling the rolling bearing of the water pump
The disassembly of the rolling bearing of the water pump is carried out during regular maintenance or when the rolling bearing of the water pump needs to be replaced due to abnormal operation. Regular maintenance needs to replace the rolling bearings of the water pump. When disassembling the rolling bearings of the water pump, it is necessary to understand the cause of the abnormality to prevent the abnormality from recurring. At least the following items should be retained.
1) Collect and keep the used lubricant.
2) Keep the damaged water pump rolling bearings.
3) Keep records of abnormal events during operation.
4) Keep records of the rolling bearings of the water pump during abnormal operation.

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