Bearing Assembly Requirements and Maintenance Methods

Precautions before bearing installation

1. Check the bearing for quality problems. Whether the rotation is flexible, carefully check the bearing parts for defects, such as indentation, burns, cracks, etc. It is strictly forbidden to install parts with quality problems.

2. Make sure the installation site is clean and prevent foreign matter from entering the bearing.

3. Make sure the bearings are clean, and do not install bearings that have not been cleaned.

4. Ensure the sealing quality. Carefully check whether the model specifications and sizes of the seals are appropriate, whether there are defects or quality problems, whether the related accessories are complete, and whether the cooperation is reasonable.

Precautions during bearing installation

1. Avoid hard mounting and impact. Be sure to gently install the bearing. The bearing and the seat hole have a small clearance. Normally, the end face should be tapped into the normal position. Surface wounds and even scrapped.

2. The bearing inner sleeve must be heated by induction and must not exceed 120°C. It is strictly forbidden to disassemble and assemble bearings by open flame.

3. When it is not easy to install, find out the reason, take reasonable measures after eliminating the problem, and timely repair when there are problems such as parts deformation, and if necessary, please revise the drawings.

4. Inject sufficient and clean grease in strict accordance with requirements.

5. When unqualified seals, glands and other parts are found in the installation, they must be strictly scrapped or repaired to ensure that the assembly quality meets the quality requirements.

Precautions for bearing disassembly

1. When the phenomenon of burning bearings is found, first of all, it is necessary to clarify the frame and bearing housing in time and make a record. In turn, check whether the lubricating oil is sufficient-whether it is water or oxide scale, whether the seal is damaged and whether the related accessories are used correctly-whether there is obvious friction relative to the rotating part-the external size of the bearing seat-the size of the seat hole, ellipse, taper 1. Make a record of whether the eccentricity and circle runout of the reference lining surface exceeds 0.05, etc., so as to further analyze the cause and take corresponding measures.

2. When removing the inner sleeve of the four-row cylindrical roller bearing, it must be heated with a bearing induction heater and must not exceed 120°C. When it is difficult to disassemble due to burning stick, it is less than a last resort, and it is strictly prohibited to burn and cut with fire.

3. In special cases, when the bearing inner sleeve must be cut with flame, it must be approved by the factory director, the reasons must be clarified and records must be made. If you decide to release it for reuse, you must go to the grinder to grind the roll neck. It is strictly forbidden to use only manual grinding wheel for simple grinding and then put it into use.

Preparation before bearing assembly

1. Preparation of measuring tools and tools

2. Inspection of parts

 Processing quality inspection of parts such as shafts, housings, end caps, bushings, seals, etc. The surface matched with the bearing should not have depressions, burrs, rust and solid particles.

3. Cleaning of parts

 Before installing the bearing, use diesel or kerosene to clean the shaft, housing and other parts, and wipe the matching surface with a clean cloth (not cotton yarn), and then apply a thin layer of oil to facilitate installation. All lubricating oil roads should be cleaned, inspected and ensured to be smooth.

4. Bearing cleaning

Bearings sealed with anti-rust oil can be cleaned with diesel or kerosene; bearings with dust caps or seal rings on both sides have been added with lubricants before leaving the factory, as long as the lubricants in the bearings are not damaged or deteriorated, when installing such bearings It is not necessary to clean; bearings coated with anti-rust and lubricating grease can also be cleaned during installation.

 The bearing should be filled with lubricant immediately after cleaning, and the bearing should be turned slowly when oiling, so that the grease enters between the rolling body and the raceway. The lubricating oil (grease) for bearings must be clean and free of dirt.

Overhaul of shaft and bearing seat

1. Overhaul of the shaft

First, use a dial indicator to check whether it is bent or deformed. If there is any deformation, turn, grind or straighten it.

 There should be no burrs or bumps on the mating surface of the shaft and the bearing, the perpendicularity of the shaft shoulder to the shaft, and the radius of the corner of the shaft shoulder should be measured.

2. Overhaul of bearing seat hole

Measure the roundness and cylindricity of the bearing housing hole, check the perpendicularity of the shaft shoulder of the bearing housing hole, etc.

Assembly of rolling bearings

1. Bearing installation with tight fit of inner ring and shaft, loose fit of outer ring and bearing seat

 The hammered end face of the assembly casing shall be processed into a spherical shape. Where there is no press or where the press cannot be used, the bearing can be installed with an assembly sleeve and a hammer.

2. The inner ring is loosely fitted with the shaft, and the outer ring is tightly fitted with the bearing seat.

Press the bearing into the bearing seat first, the outer diameter of the assembly sleeve should be slightly smaller than the diameter of the shell hole, and then install the shaft.

3. The inner ring and the shaft, the outer ring and the bearing seat are all closely fitting bearing installation

The end face of the assembly sleeve should be processed into a ring that can simultaneously compress the inner and outer ring end faces of the bearing to press the bearing into the shaft and the bearing seat hole. This method is suitable for the installation of self-aligning radial ball bearings.

4. Hot (cold) mounting method of bearings

Put the bearing or separable bearing ring into the oil and heat it evenly to 80~100℃ (should not exceed 100℃) before hot fitting, and then take it out and install it on the shaft quickly.

 When the rolling bearing is assembled by cold assembly method, it is generally not lower than -80℃ to avoid cold and brittle material.

5. Disassembly of rolling bearings

 Rolling bearings use hot assembly method, cold assembly method and hot unloading method, the advantage is that it will not destroy the interference, and the assembly and disassembly are both labor-saving and rapid.