When installing NILOS-Rings of types AV or AK in taper roller bearings, it is necessary to pay special attention to one particular point: The pivot pins of the bearing housing must be installed precisely in the centre and parallel both for horizontal and vertical installation (16.2). They can be skewed when installed, and under unfavourable circumstances the sealing edge can be damaged so much that it is no longer possible to guarantee proper sealing.
Dimension “w” applies for NILOS-Rings of type AK in the relevant dimensional tables for the diameter of the circle on which two retaining nubs are provided to prevent it from rotating. When installing the NILOS AK-type ring, it is necessary to ensure that the two retaining nubs click into the corresponding cut-outs in the shock ring or in the pivot pins.
The two retaining nubs on NILOS AK-type rings are opposed by 180°, they have a diameter at the base of around 4 mm and a height of approx. 1.5 mm. Depending on the options available for production, the bearing part to be pressed in can either have two matching recesses or – which makes easier installation possible – a 2 mm deep and 4 mm wide groove can be arranged. This groove is then interrupted by a small positioning pin that locks one of the two retaining nubs to prevent possible twisting or rotation.
A number of different processes are used in the various factories concerning the angle of incidence of taper roller bearings. A distinction is made between the following procedures, among others:
1. Tightening up the bearing thread until the axial play is “0” (16.3) by using a standard spanner. Then the screw connection is undone by a certain amount (1/6 to 1/12 turn)
in order to produce the desired bearing play and thus lock the screwed connection (16.4).
2. Tightening up the screw connection with a torque wrench to a previously determined and always consistent torque. Then loosening and locking the screw connection as described in 1. above.
3. Tightening up the screw connection either with a standard spanner, then undoing the screw connection and measuring the axial play of the bearing, and correcting the axial play as necessary by loosening or tightening the screw connection further. Locking the screw connection once the desired axial play has been reached.
NILOS-Rings of type AV or AK can be installed without any problems for all types of setting-up. The axial forces to be aimed at in setting up the bearing with the screw connection are several times higher than the force acting on the NILOS-Ring sealing edges. The force acting on the NILOS-Ring sealing edge is thus to some extent perceptible when turning the bearing. Thus under no circumstances should it be assumed that the bearing does not have the necessary axial play. The NILOS-Ring has been run in after the shortest possible running time at operating r.p.m..
The elasticity of the NILOS-Ring material also makes it possible to measure the axial play of the bearing. Thus there is no danger that the sealing edge of the NILOS-Ring lifts up from the taper roller bearing or will remain deformed when measuring the axial play.
The intrinsic elasticity of the NILOS-Ring is many times higher than the normal permissible axial play of the bearing.
There must be at least 1 mm clearance between the NILOS-Ring and the adjacent machine part behind the outside diameter of the NILOS-Ring.