EXPERIMENTAL INVESTIGATION OF A LARGE TILTING-PAD JOURNAL BEARING WITH A DIRECT-BONDED SUB-MILLIMETER PEEK LINING

A novel coating technique allows direct bonding of polymer material to large plain bearings, enabling lower-cost manufacturing, more flexible running layer design and thin-layer coatings. In this publication, experimental results for a 500mm tilting-pad journal bearing (TPJB) with a direct bonded sub-millimeter polyether ether ketone (PEEK) lining are presented. The five-pad TPJB in a non-flooded design is investigated on a test rig for original sized turbine bearings over a speed range of 1000 rpm - 3600 rpm. With the test rig, fluid film pressure and the distance between the shaft and the pads backing are measured from the rotating and axially shiftable shaft. By knowing the permittivity of the PEEK material and the thickness of the liner, the fluid film thickness is calculated from the data of a capacitive distance sensor. The experimental data are compared with those obtained with an identical bearing with Babbitt as lining material. The results show markedly lower pad backing temperatures for the PEEK lined pads than for the Babbitt-lined pads and a reduction in their axial deflection is detected with the PEEK lined pads. Therefore, the test bearing can be loaded up to 4.75MPa (at 3000 rpm) in the experiments.