A pump is used to provide pressurised oil to the nut. The permissible stroke (axial
displacement) has been chosen to enable all bearings having bores with a taper of
1:12 or 1:30 to be mounted in a single operation. The permitted piston displacement,
which is indicated by a groove in the outside of the piston, should not be exceeded. After
mounting has been completed, the return valve of the pump should be opened so that
the pressurised oil can leave the nut. To completely empty the nut, the piston has to be
returned to its original position. This is most easily accomplished by threading the nut
further up the shaft or sleeve thread, causing the piston to retract. This causes the oil to
low back to the pump.
2.4 Dismounting of bearings
When dismounting rolling bearings from withdrawal or adapter sleeves, the hydraulic nut
is screwed onto the sleeve thread until it rests against the bearing inner ring (ig. 7) or a
special support ring (ig. 8). By displacing the piston, the sleeve will be withdrawn from the
bearing bore or the bearing will be pressed off the adapter sleeve.
Dismounting
Figure 7.
HMV nut used to free a withdrawal
sleeve
2.5 SKF Drive-up Method for mounting bearings with a tapered bore
Traditionally the radial internal clearance reduction has been measured when mounting
bearings with a tapered bore. The accuracy of this method is highly dependent on the
technician being skilled in the use of feeler gauges applied to the measurement of the
clearance reduction. The SKF Drive-up Method considerably improves the reliability and
ease in itting bearings with a tapered bore and can be used for SKF spherical roller
bearings, SKF CARB
®
method, you will need a pump with a highly accurate digital pressure gauge and a dial
indicator (ig. 9). Pumps with the sufix DU are supplied with a digital gauge reading from
0 - 100 MPa (0 - 15 000 psi).
8
Il Cuscinetto srl - www.ilcuscinetto.it - info@ilcuscinetto.it
, and some SKF self-aligning ball bearings. To be able to use the
Figure 8.
HMV nut and stop ring in position to
press loose an adapter sleeve
SKF HMV / HMVC