Kingsbury bearing maintenance technology

Thread Content

1) Disassembly procedure for Kingsbury-type thrust bearings: ① Remove the shaft displacement probe and other instrument connections; after measuring the clearance of the thrust bearing, remove the cover on the bearing housing as well as the cover on the thrust bearing shell. ②Remove the thrust bearing and shims on the non-working side, and mark the position of each bearing pad. When removing it, be careful not to damage the temperature sensing wires of the tile. ③Install the upper cover of the bearing seat on the thrust bearing housing. Tighten the mid-surface screws and set screws, and check the clearance of the first-stage nozzles (for turbines) or the half-rotation amount of the rotor (for compressors) before removing the cover. ④Remove all the upper covers, as well as the thrust bearing on the working side and the oil seals in front of and behind the thrust bearing. 2) Technical requirements for the maintenance of Kingsbury-type thrust bearings ① Thrust pads a. The babbitt layer of the thrust pads shall be free from defects such as delamination, wear, cracks, burning, crushing, roughening, and erosion. The tiles were inspected by coloring or dipping in kerosene, and the babbitt bonded well with the base metal. b. The surface of the thrust bearing pads must not have any radial grooves or scratches; the depth of circumferential grooves or scratches shall not exceed 0.10 mm, and the pads must not suffer from uneven wear. c. Use red lead to check the contact between the babbitt surface of each individual tile and the surface of the thrust plate; the contact area should be at least 80%, and the thickness variation among tiles in the same group should not exceed 0.015 mm. d. The load-bearing surface on the back of the tile is smooth, with no signs of heavy loading such as burning, bonding, or indentations. The tile load-bearing pads should be firmly fixed to the tiles, without any looseness. e. The babbitt on the oil-inlet side of the tile has a smooth transition to facilitate oil inflow and the formation of an oil film. f. For thrust pads equipped with thermistors, it is necessary to check the firmness of the fixation of these thermistors within the pads; the temperature sensing wires should not interfere with the free movement of the pads. The thermosensitive element and leads, together with the tile, are inspected by the instrument; the insulation and measurement accuracy meet the instrument’s specifications. ②Base ring and voltage equalizing block: a. The load-bearing surface of the voltage equalizing block is smooth, with no signs of heavy loading such as wear, scorching, or indentations. It swings freely within the base ring without getting stuck. The stop pin has an appropriate length and is securely fixed; it maintains sufficient clearance from the pin holes of the voltage equalizing block, so as not to press against the block or cause uneven wear on the pin holes. b. There are no indentations on the contact lines between the working surfaces of the voltage equalizing blocks; their surfaces are smooth, and they can move freely relative to one another. c. The base ring shows no warping; the joint surface between the two halves of the base ring is smooth with no cracks, and there are no indentations at the points where it contacts the pressure equalizing block. The back surface of the base ring exerts even pressure on the end face of the thrust bearing. ③Thrust disc a. The surface of the thrust disc must be smooth and even; the surface roughness should be at Ra0.8. Radial grooves are not allowed, and the depth of circumferential grooves should not exceed 0.05 mm. b. The thrust disc is connected by keys; there are no signs of compression between the keys and the keyways, and the keyways have been inspected for cracks and show none. The thrust disc makes even contact with the shaft shoulder and the end face of the back sleeve; the key is properly fitted in the keyway of the thrust disc, and the side clearance, top clearance, as well as the fit between the thrust disc and the shaft meet the design requirements. The total runout of the end face of the assembled intervertebral disc is less than 0.015 mm. c. When a hydraulic assembly and disassembly thrust disc structure is used, it is necessary to check the contact condition between the inner hole of the thrust disc and the surface of the spacing cone sleeve, as well as the contact condition between the end face of the cone sleeve and the shaft shoulder; these contact ratios must be at least 80%. There should be no burrs, scratches, or damage on any of these surfaces, and the fit between the inner hole of the cone sleeve and the shaft must not be out of specification. d. The circumferential deviation of the thrust disc thickness shall not exceed 0.005 mm. ④Oil seal: a. The front and rear oil seals show no wear, scratches, or axial grooves; after tightening the screws on the split surface of the oil seals, these seals rotate freely within their respective grooves around the axis, with no misalignment or gaps at the split surface. After the upper bearing cover is fastened, the oil seal moves freely. b. The radial clearance between the oil seal and the shaft shall not exceed 0.05–0.10 mm. ⑤Bearing housing (for those with thrust bearings): a. There should be no misalignment gap between the upper and lower thrust bearing housings after tightening the split-screw; once the thrust bearings are installed, they should not press against the bearing housing. b. The thrust bearing housing should be properly tightened within the bearing housing, with the axial clearance not exceeding 0.01–0.03 mm. The thrust bearing adjustment shims are firmly fixed within the bearing housing. c. The oil inlet hole on the bearing housing is not blocked, it is aligned with the oil inlet hole of the bearing seat, and the screw securing the oil inlet plate is firmly fixed within the bearing housing without any looseness. d. The thrust pads show no signs of wear or indentation inside the thrust bearing housing. ⑥Flat thrust bearing on the non-working side: a. The bearing plate is smooth, flat, and free from warping, with a thickness variation of less than 0.01 mm. b. Its outer diameter is 1.0 mm less than the inner diameter of the shell.