How to install bearings on a shaft

First of all, we need to know that before installing, we need to know some things we install

1. Whether the size of the bearing and the bearing body and the requirements for the shaft, and whether the corners of the machined shaft and the bearing body have right-angled contact surfaces, and whether they can make sufficient contact.

  1. Determine whether the matching oil surface of the bearing fine body has abrasions, sandpaper, etc. There is dust or mold sand on the surface of the casing, etc. Grinding stones, cleaning cloths, etc. may be required or not.
  1. Bearing installation – When the bearing is installed on the shaft, pay attention to the force of the outer ring. When it is installed on the bearing body, the bearing must be forced. 3: The bearing is on the shaft, and it is not allowed to install and knock the bearing on the outer ring of the bearing. Such operations must not be performed. The track fault surface must be applied, which will cause noise and traces of the pressure and physical force at that time, which will affect the bearing when the bearing is subjected to external force. In addition, it is also guaranteed that the capacity of the bearing remains absolutely unchanged.
  1. Bearing installation – installation using hammer and sleeve The installation method of using hammer and sleeve is the most commonly used method. Be sure to make the sleeve in the middle as shown in the figure and tap in, and the hammer should be tapped lightly. .
  1. Bearing installation – When the inner and outer rings are installed at the same time, on the mechanical structure, when the inner and outer rings are tightly fitted, a backing plate should be used, and the force must be applied to the inner and outer rings at the same time. If an external force is applied only to the inner ring, the force must be pressed into the outer ring by the balls, so a scratch may be caused on the raceway surface.
  1. Lastly, the finale of assembly of rolling bearings.

The correct and safe installation steps for bearings on to a shaft

  1. Use special tools for bearing installation and disassembly

Advanced installation tools can avoid bearing damage caused by improper tools and operations during installation. For example, when installing the bearing, the staff used the copper rod knocking method, which is easy to cause uneven axial force on the bearing, causing deformation of the cage, damage to the rolling elements, and large clearance. The copper powder flies into the bearing cage, which is easy to cause bearing failure.

  1. Check the bearing before installation

For old bearings, check the ball (column) surface for burrs, scratches, cracks. Whether the radial clearance and axial clearance of the old bearing are qualified, generally only the radial clearance is measured. For new bearings, first check that the bearing type is correct. Refer to Table 1 for the radial clearance standards of rolling bearings. For example: Model 6318 deep groove ball bearing, the inner diameter of the bearing is 90mm, the radial clearance range is 0.016 ~ 0.046mm, and the maximum wear amount of the bearing can also be found to be 0.25mm.

  1. Control the quantity of bearing and bearing chamber oil

 

Too much oil in the bearing and the box will cause the bearing rolling element to slip, causing the rolling element to change from rolling friction to sliding friction, and damage the bearing rolling element. Due to the excessive amount of bearing oil, the free space in the bearing box is small, and the operating temperature of the bearing will rise. The degree of lubricating grease decreases, the lubricating oil film of rolling elements becomes thinner, and the lubricating conditions are poor, which is easy to cause abnormal noise of the bearing, surface slippage, and shorten the life of the bearing. Generally, there is a bearing oil chamber on the side of the motor end cover (except for motors designed with double-sealed bearings). According to the speed of the motor, the amount of oil that can be filled in the bearing chamber can be implemented according to the following standards: when the motor speed is less than 1500r/min, the amount of oil added is the bearing chamber. 2/3 of the volume. When the speed is between 1500 and 3000r/min, it is 1/2 of the bearing chamber volume. When the speed is more than 3000r/min, it should be less than or equal to 1/3 of the bearing volume. In the actual working process, for the bearings running at high temperature and high speed, the bearings with sealing surfaces should be used as little as possible, the oil storage capacity of the motor oil cap should be increased, and the oil nozzles should be installed to improve the operating life of the motor bearings.

  1. Pay attention to ensure when the insulation is intact.

For bearings with an insulating design on the outer ring, care should be taken to ensure that the insulation is intact. If the bearing insulation is damaged during installation, the very thin bearing oil film will be broken down by the shaft voltage. After the oil film is broken down, not only will the lubrication conditions of the rolling elements be poor, but also the electric sparks generated will cause electrical corrosion to the rolling elements of the bearing, causing rolling elements. The surface is not smooth, which accelerates the wear of the bearing.

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