When installing self-aligning roller bearings for crushers, comprehensive control should be taken from multiple aspects such as environmental cleanliness, tool preparation, bearing inspection, installation methods, centering positioning, clearance adjustment, post installation inspection and debugging. Specific precautions are as follows:
1. Preparation before installation
Environmental cleanliness: Ensure that the installation area is free of dust and metal debris to avoid contaminating the bearing raceway.
Tool preparation:
Special tools: such as bearing heaters, micrometers, bearing pullers, or hydraulic jacks.
.Measuring tool: Use a micrometer to measure the shaft diameter and bearing inner diameter, ensuring that the fit size meets the requirements.
.Lubricant selection: Choose the appropriate lubricant based on the bearing speed and load, such as lithium based grease or high-temperature composite grease, and apply it to the bearing raceway and cage.
.Bearing inspection:
Check the bearing model and specifications to ensure they are consistent with the equipment requirements.
.Check the appearance for any damage and confirm that the holder is intact and undamaged.
. Measure the fitting dimensions to ensure the accuracy of the fit between the bearing, shaft, and bearing seat.2. Installation Method
Cold and Hot Installation Selection:
Cold Installation: Suitable for small-sized bearings, use liquid nitrogen or dry ice to cool the bearing to around -40 ℃, shrink the inner ring of the bearing, and then install it.
.Hot fitting: Suitable for bearings with large interference fit, use an oil bath (oil temperature 80-120 ℃) or induction heater to heat the bearing to 80-100 ℃ (maximum not exceeding 120 ℃), expand the inner ring of the bearing, and then install it.
. After heating, a copper rod should be used immediately to apply uniform force along the inner ring to avoid local deformation caused by stress.Installation steps:
Bearing seat preparation: Clean the bearing seat hole, check the fit size and surface roughness, and apply an appropriate amount of lubricating grease.
. Bearing installation: Handle with care to avoid collision. Ensure that the bearing is pressed vertically, using a dedicated sleeve or press to avoid transmitting pressure through the rolling elements. For bearings with separable inner and outer rings, the inner and outer rings should be installed separately.Positioning fixation: Use shaft shoulders or elastic retaining rings to fix the bearing end face, avoiding axial movement.
. Use a dial indicator to detect the axial displacement and ensure that the positioning error is ≤ 0.02mm.Clearance control:
Adjust the appropriate clearance according to equipment requirements.
. Excessive clearance can cause vibration, while insufficient clearance can cause overheating.Adjustment method:
Gasket method: Add or remove shims between the bearing end face and the shaft shoulder, suitable for outer ring non separable bearings.
. Nut pre tightening: For separable bearings (such as four point contact ball bearings), the clearance is controlled by tightening the nut.Target value setting: Select C0~C3 group radial clearance under normal working conditions (standard to slightly loose); Select C3~C4 groups under high temperature/heavy load conditions, and reserve thermal expansion space.
Lubrication Management:
Apply an appropriate amount of lubricating grease on the mating surface before installation, with the lubricant filling amount generally 1/3~1/2 of the internal space of the bearing.
. Ensure smooth lubrication channels and avoid grease blockage.Sealing protection:
Install the seal correctly and ensure that the direction is correct.
. Check the contact between the sealing lip and the shaft to prevent impurities from entering.4. Inspection and debugging after installation
Manual testing:
Rotate the bearing manually to check if it is smooth and unobstructed.
. Confirm that there are no abnormal noises or friction.Running test:
Run without load for 30 minutes and monitor the temperature rise (generally not exceeding the ambient temperature+35 ℃).
. Check if the vibration value is within the allowable range (such as ISO 10816 standard: precision equipment vibration ≤ 1.8mm/s).Final tightening:
Confirm that all fasteners have reached the specified torque value.
.Use anti loosening measures (such as locking washers, thread glue, etc.).