Installation and disassembly of miniature bearings and their use environment

Installation, disassembly and use environment of miniature bearings

1.Installation of miniature bearings:

The installation of miniature bearings must be carried out in a dry and clean environment. Before installation, the machining quality of the matching surfaces of the shaft and the housing, the end faces of the bosses, the grooves and the connection surfaces should be carefully checked. All matching connection surfaces must be carefully cleaned and burrs removed, and the unprocessed surfaces of the castings must be free of molding sand.

Before installing the miniature bearing, it should be cleaned with gasoline or kerosene, dried and used, and good lubrication should be ensured. Miniature bearings are generally lubricated with grease, and oil lubrication can also be used. When using grease lubrication, grease with excellent properties such as no impurities, anti-oxidation, anti-rust, and extreme pressure should be selected. The amount of grease filling is 30%-60% of the volume of the miniature bearing and the miniature bearing box, and it should not be too much. The double-row tapered roller miniature bearings with sealing structure and the water pump shaft miniature bearings have been filled with grease, and users can use them directly without cleaning.

When installing the miniature bearing, it is necessary to apply equal pressure on the circumference of the end face of the ferrule to press the ferrule in. Do not use tools such as hammers to directly hit the end face of the miniature bearing to avoid damaging the miniature bearing. When the interference is small, the end face of the miniature bearing ring can be pressed with a sleeve at room temperature, and the sleeve can be hit with a hammer to press the ferrule evenly through the sleeve. If it is installed in large quantities, a hydraulic press can be used. When pressing in, it should be ensured that the end face of the outer ring is pressed against the end face of the outer shell shoulder, and the end face of the inner ring is pressed against the end face of the shaft shoulder, and no gap is allowed.

When the interference is large, the Dongguan miniature bearing method of oil bath heating or induction heating can be used for installation. The heating temperature range is 80℃-100℃, and the maximum cannot exceed 120℃. At the same time, nuts or other appropriate methods should be used to tighten the miniature bearing to prevent the miniature bearing from shrinking in the width direction after cooling, which will cause a gap between the ferrule and the shaft shoulder.

The clearance of the miniature bearing should be adjusted after installation. The clearance value should be determined according to different working conditions and the size of the interference fit. If necessary, it should be determined by testing. The double-row tapered roller miniature bearings and the miniature bearings for water pump shafts have been adjusted for clearance at the factory, and no adjustment is required during installation.

After the miniature bearings are installed, a rotation test should be carried out. First, they are used for rotating shafts or Dongguan miniature bearing boxes. If there is no abnormality, they are operated without load and at low speed by power. Then, the rotation speed and load are gradually increased according to the operating conditions, and noise, vibration and temperature rise are detected. If abnormalities are found, the operation should be stopped and checked. They can only be delivered for use after the operation test is normal.

2. Disassembly of miniature bearings:

When the miniature bearings are removed and are to be used again, appropriate disassembly tools should be used. When disassembling the interference fit ring, only the pulling force can be applied to the ring, and the disassembly force must not be transmitted through the rolling element, otherwise the rolling element and the raceway will be crushed.

3. The use environment of miniature bearings:

Selecting the specifications, dimensions, and precision according to the use parts, use conditions and environmental conditions, and matching suitable miniature bearings is the premise for ensuring the life and reliability of miniature bearings.

1. Used parts: Tapered roller miniature bearings are suitable for bearing radial and axial combined loads dominated by radial loads. They are usually used in pairs of two sets of miniature bearings. They are mainly used in the front and rear wheel hubs, active bevel gears, differentials, reducers and other transmission parts of automobiles.

2. Allowable speed: Under the condition of correct installation and good lubrication, it is allowed to be 0.3-0.5 times the limit speed of Dongguan miniature bearings. Under normal circumstances, 0.2 times the limit speed is appropriate.

3. Allowable tilt angle: Tapered roller miniature bearings generally do not allow the shaft to be tilted relative to the housing hole. If there is a tilt, it should not exceed 2'.

4. Allowable temperature: Under the condition of bearing normal loads, the lubricant has high temperature resistance, and the lubrication is sufficient, general miniature bearings are allowed to work at an ambient temperature of -30℃-150℃.