Installation and maintenance technology of tower crane slewing bearing:
1. The mounting support of slewing support must be sufficiently rigid and the mounting surface should be flat. The bearing should be de-stressed before assembling the slewing bearing to reduce the deformation of the bearing. The contact surface between support and slewing support must be cleaned during assembly.
2. During the maintenance and use of the tower crane, it should pay attention to the change of noise and the change of rotary resistance moment. If there is any abnormal phenomenon, it should be dismantled and inspected.
3. The slewing support must be lifted or stored horizontally. Do not lift or store vertically to avoid distortion.
4. Before the bolts are fully tightened, the meshing inspection of gears should be carried out. Its meshing condition should meet the requirements of slewing gear
accuracy: that is, after the gear pair operates under slight braking, the contact spots distributed on the tooth surface shall be no less than 25% in the direction of the height of the gear tooth and no less than 30% in the direction of the length of the gear tooth. The tooth surface should be cleaned once for 10 shifts and greased again.
5. In order to ensure the reliability of bolt operation and avoid the shortage of bolt pre-tightening force, the pre-tightening torque of bolt should be checked respectively after the first 100 hours and 500 hours of rotary support operation. The pre-tightening torque shall be checked every 1000 working hours thereafter.
6. The bolts and nuts connecting the slewing ring turntable bearing
are high-strength bolts and nuts maintained by tower crane. Double nut is used to tighten and prevent loosening.
7. When tightening the nut, the thread of the bolt and the end face of the nut should be lubricated, and the nut should be tightened symmetrically and evenly with a torque wrench in the circumferential direction for several times. For the last tightening, the pre-tightening torque on each bolt should be roughly uniform.
8. Four oil cups are placed on the upper surface of the gear ring of the slewing support to align with the raceway, thereby adding grease to the raceway. Under normal conditions, the slewing bearing can be lubricated once in 50 hours. Each refueling must be done until oil seeps from the seal.