Investigation on the influence of cavity shape on oil film morphology in hydrostatic thrust bearings

The rotation accuracy and load-carrying capacity of hydrostatic thrust bearings are significantly influenced by cavity shape. To investigate the influence of cavity shape on oil film morphology, the lubrication mechanism of three cavity shapes, including double rectangular, sector, and runway, was deduced by tribology theory. The friction-pair deformation and oil film morphology were analyzed using a fluid-thermal-solid coupling approach. The effects of cavity shape on oil-film morphology were analyzed under different rotational speeds and loads, and the effectiveness of the numerical procedure was experimentally validated using oil-film-thickness measurements from the double rectangular hydrostatic thrust bearing. Results indicated that under high-speed conditions, the largest deformation of the oil sealing edge occurred at the inner upstream side; the minimum oil-film thicknesses ranked from the largest to the smallest in the order of sector, runway, and double rectangular cavities, with corresponding values of 0.0414 mm, 0.0362 mm, and 0.0165 mm. Under heavy-load conditions, the deformation on the inner side of the oil sealing edge was larger than that on the outer side, and the deformation on the upstream side was larger than that on the downstream side. The minimum oil-film thicknesses ranked from the largest to the smallest in the order of runway, sector, and double rectangular cavities, with corresponding values of 0.0409 mm, 0.0361 mm, and 0.0305 mm.