Determine the bearing positions and where possible install the fixed bearing first, as this then locates the shaft axially. Wipe clean all bearing parts to remove preservative oil before fitting. All split components have marking numbers at the joint to identify matching halves. Lightly oil the shaft with thin oil. Other interfaces and threads should also be lubricated.
Clean and inspect the shaft at the bearing seating. Determine the tolerance required from the table provided. When the two halves of the inner race are assembled around the shaft there should be a gap at each joint. This feature ensures the race is gripped to the shaft securely by the clamping ring halves. Maintain even joint gaps on the inner race and clamping rings. Soft packing can be used to equalise the inner race joint gaps. Fit the clamping rings with their joints approximately 90° to the inner race joints. Progressively tighten the clamping ring joint screws keeping all gaps equalised. With a soft faced hammer, tap the clamping ring halves to seat in their grooves. Finally, tighten the joint screws to the torque figure indicated in the provided table.
For expansion bearings, the inner race can be offset according to the amount of shaft thermal expansion, so that when operating temperature is reached, the rollers will run central to the outer race. When fitted, re-check the inner race and clamping ring joint gaps are equal, and the race is correctly positioned axially.
The radial cage is supplied with some loose rollers, which join the cage halves once assembled on the inner race. Apply a film of grease to the roller path and bore of the cage before placing the cage around the race. Insert the joint coupler with its bevel edge toward the shaft. The cage halves do not have matching numbers, instead they have a male / female tenon. With the two halves around the inner race, fit the loose rollers with firm pressure until they lock in the pockets and retain the halves of the cage. Couplers can be fitted to one half of the cage before the cage is fitted. Rotate the cage to assemble the second joint.
Individual instructions are supplied with each seal. Separate the seal halves using the release tool provided. Lubricate the bore of the seal and the shaft with a thin film of grease. Place the two halves of seal around the shaft ensuring the male / female joints correspond and compress the ‘O’ rings to clip the halves together. Once fitted, the seals can be moved axially to position them relative to the housing grooves (when the housing is fitted)
Prime the small radial groove of the inner housing with grease. Take the radial outer race halves, the upper half is identifiable by the radial lubrication holes and must be fitted in the housing top half which has the lubrication nipple. Push the race halves into the seating grooves ensuring match numbers are adjacent. The race joints will protrude slightly beyond the housing joints. Protect these faces when handling the halves.
For fixed bearings, place the axial races in their recesses as shown. When pushed fully into their seating, the joints of the axial races will be slightly below the face of the housing.
Apply lubricant to the inside surface of the housing, covering the fitted races. Coat the assembled cages & rollers on the inner race and add some grease to the labyrinths of the seals. The quantity of grease to be used in the bearing can be determined from the grease weights table.
With the pedestal base located in position, place the lower half of the inner housing on top of the shaft. Lubricate the spherical surfaces of pedestal and inner housing. Align the two spherical surfaces, ensure the labyrinth seals mate with their corresponding grooves and rotate the housing around the shaft into the pedestal base and both joint faces are aligned. It may be necessary to manually guide the axial rollers into position between the clamping rings and axial outer races whilst rotating the housing into position.
Place the upper half of the inner housing on top of the shaft in position ensuring the axial rollers & races align. Lower gently into position, then fit and progressively tighten the housing joint screws.
Shaft supports or jacks can now be removed.
Apply a thin film of grease to the spherical surfaces of pedestal cap and upper half of inner housing. The pedestal cap can now be fitted, ensuring the matching numbers are together. Fit the joint screws, tighten then release approximately half a turn.
Rotate the shaft by hand or under power for a few revolutions before finally tightening the cap screws. This allows the housings to align the bearing with the shaft.
- Clean bearing parts and shaft before installation
- Measure shaft to ensure it is within tolerance
- Keep matched component halves together
- Equalise joint gaps on both sides of inner race and clamp rings
- Inner race must be fully tightened
- Lubricate bearing during assembly NOT after
- Lubricate seals bores, labyrinths and housing spherical surfaces
- Tighten screws according to torque figures provided
Screw Sizes and Tightening Torques
Greases of NLGI No. 2 designation are recommended for most applications. For centrally pumped systems a No. 1 grease may be used for increased pumpability.
Greases with extreme pressure (EP) additives are recommended. However, JHB split bearing units do not rely upon EP greases being used to achieve the axial capacities listed, unlike existing manufacturers units.
Grease with a lithium complex thickener is usually used for normal applications operating at temperatures between 0° and 80°C. When water resistance is required a grease with an aluminium complex thickener can be used. Some greases are immiscible with each other so if changing lubricants, the bearing unit must be solvent-cleaned of the old lubricant before using the new lubricant.
Please contact our Technical Department if lubrication advice is required.
Grease quantity for initial lubrication
The quantity of grease required for initial lubrication is dependent upon operating speed. For slow applications, the bearing and housing can be packed full of grease, however at higher speeds excessive grease will cause the bearing to overheat.
The table below shows the fully packed quantity of grease for each housing size. The actual amount should be estimated using the percentage of this quantity factored according to the shaft speed.
Estimation of the quantity required depending on the speed can be made using the tables below:
Fully packed grease quantity:
Re-lubrication quantity should be around 2 – 3 grams given at the following interval:
Radial bearing with axial bearing (fixed or thrust arrangement):
> 100 operating hours
Radial bearing only (expansion arrangement):
> 400 operating hours