Assembly Methods of Flexible Bearings

I. Preparation before Assembly

1. Cleaning and Inspection:
   Before assembly, the flexible bearing should be thoroughly cleaned with gasoline or kerosene to remove the oil stains and impurities on the surface. After cleaning, the bearing should be air-dried and ensured to be well lubricated. Carefully check the model, size, and surface quality of the bearing to ensure that there are no defects such as cracks and scratches.
2. Lubrication Selection:
   Flexible bearings generally use grease lubrication, and oil lubrication can also be used. When selecting the lubricating grease, priority should be given to the lubricating grease with excellent performance such as being free of impurities, anti-oxidation, anti-rust, and extreme pressure resistance. The filling amount of the lubricating grease should be controlled between 30% and 60% of the volume of the bearing and the bearing housing, and it should not be too much or too little.

II. Assembly Methods

1. Press-fitting Installation Method:
   This method is suitable for small flexible bearings. Use a press or special tools to evenly press the bearing onto the shaft or into the bearing seat. During the pressing process, ensure that the force is evenly applied to avoid damaging the bearing.
   When the interference fit is large, the method of heating the bearing by oil bath or inductor can be used to increase the installation temperature. The heating temperature should be controlled between 80°C and 100°C, and it should not exceed 120°C to prevent the bearing material from becoming brittle.
2. Thermal Expansion and Contraction Installation Method:
   This method is suitable for medium and large flexible bearings. It includes two methods: the hot installation method and the cold installation method.
   • Hot Installation Method: Heat the bearing to 80°C - 100°C to make its inner diameter expand, and then quickly put it on the shaft. Special heating equipment should be used during the heating process, and ensure that the heating is uniform.
   • Cold Installation Method: Use cooling media such as liquid nitrogen to cool the shaft to make its outer diameter shrink, and then easily put the bearing on the shaft. The cold installation method is suitable for occasions where it is difficult to heat the bearing.
3. Tapping Installation Method:
   This method is suitable for flexible bearings with clearance fit. During the tapping process, soft materials such as copper rods or soft iron should be used as tapping tools to avoid damaging the bearing. When tapping, apply force evenly, and avoid tapping only on one side or using excessive force, which may cause the bearing to be skewed or damaged.
4. Special Assembly Methods:
   For some flexible bearings with special structures, such as bearings with an extra-large ball filling angle design, special assembly methods can be used. For example, when the ball filling angle is greater than 195°, an arc-shaped groove slightly larger than the diameter of the steel ball can be opened in the distance from the inner and outer ring ribs to the bottom diameter of the groove, and then the steel balls can be filled into the groove one by one.
   Another method is the elastic filling method. Within the allowable tensile stress range, the groove is filled by expanding the radial deformation of the bearing ring. This method theoretically can meet the requirements of 360° ball angle filling.

III. Precautions during Assembly

1. Prevent Contamination: During the assembly process, prevent pollutants such as dust and metal shavings from entering the inside of the bearing to avoid affecting the service life of the bearing.
2. Control the Force: When pressing or tapping the bearing, control the force to be moderate to avoid damaging the bearing.
3. Inspection and Adjustment: After the assembly is completed, check whether the parameters such as the rotational flexibility and axial clearance of the bearing meet the requirements, and make adjustments as needed.