1. Remove the large A105 slewing ring
(1) Disassembly process
After the top door fuse is fixed, use two 5T chain hoists, one end is hung on the lifting lugs on both sides of the bearing frame, and the other end is hung on the bearing bolt hole on the anchor bolt to adjust and stretch the gap on both sides. Before stretching, use the screw jack to lift it up and then pull it out. During the stretching process, adjust the position of the hanging bolt in the bolt hole according to the situation to adapt to the clearance on both sides and the clearance of the pinion for pulling out. When it is pulled to the half position, hang the special rope buckle for hoisting, pull the large slewing ring to the hoisting position on the frame, and command the gantry crane driver to hoist the slewing ring.
(2) Procedure for installing a new slewing ring
Before installation, pay attention to clean the new slewing ring, add grease, and block the oil passage cavity with the oil filling hole. Before hoisting, lift the large slewing ring 200mm off the ground for horizontal adjustment, so as to keep the large slewing ring horizontal and avoid side sliding after being placed on the support. To avoid shearing the base, add a small amount of lubricating oil into the base. After stretching in place, use the four lifting lugs in the cylinder to adjust the position of the large slewing ring. After the bolt holes are aligned, prepare to process the mounting surface.
2. Machining and cleaning of A105 slewing bearing mounting surface
Clean and measure the upper and lower flange surfaces before installing a new slewing ring. The measurement process is as follows: the diagonal personnel hold a thin steel wire rope, select the high point on the diameter as the reference point, and measure the sag of other points on the same straight line with a feeler gauge. The limit large feeler gauge that the non-contact steel wire can be put into the gap is sag, and the data of at least eight points of two mutually perpendicular straight lines shall be measured.
After measurement, a new A105 slewing ring can be installed. If the new rotary bearing is first positioned on the flange surface, the relative flatness of the joint surface and the upper flange surface of the rotary bearing must be adjusted, and then the output pinion of the rotary motor is adjusted, and the gear surface of the pinion can be combined with the 1/3 surface of the big gear ring. If the two pinions interfere, remove one of the pinions, send high voltage power to the gantry crane and rotate in gear 1 to see if there is radial movement or play. The knife holder can only be installed after it is stable. The flatness of tool holder and slewing bearing shall be accurate, and the machining accuracy of upper flange surface can be guaranteed only when the accuracy is within 0.2mm.
3. Decentralization process of demolition insurance
After processing, cut the A105 slewing bearing frame and wind shield. After the channel steel is cut in the reverse position, the reverse support can be placed only after it is polished smooth with an angle grinder. The descending process of the gantry crane is the reverse operation of the jacking process, and the operation process needs to follow the unified command of the same commander. During each descent, the measurement and adjustment shall be carried out within 50mm to ensure that the error of four points is within 5mm. The gantry crane can descend only after one reverse gear. Before the bolts are completely placed in place, punch all bolts in place and adjust the position of slewing ring so that the bolts are free from shear force.
4. Bolt tightening process
After the A105 slewing ring is fully in place, hold the upper and lower nuts of the stud by hand to ensure that at least 3 buckles are exposed, and add a high-strength flat pad under the nut. Do not use spring pads. After adjusting the positioning of the A105 slewing ring, pre tighten it with a torque wrench for three times: low, medium and high, and tighten it symmetrically in the direction of crossing 180 degrees. The sequence of steps shall be in accordance with the operation manual. Then the pre tightening force of the installation bolt reaches 70% of the yield strength of the bolt, that is, the pre tightening force of grade 10.9 bolt is 665kn.
5. Commissioning
After installing accessories, such as A105 slewing ring, intermediate slip ring, electrical and centralized lubrication, oil pan, pinion, etc. The large slewing bearing shall be oiled for test run. Use the first gear to rotate for test run, check the meshing condition of the tooth surface, listen to whether there is abnormal noise during rotation, measure whether the radial runout clearance of the tooth pitch circle is less than 0.7mm, and whether the joint clearance between the slewing ring and the flange surface is less than 0.2mm, test the second and fourth gears again, and confirm that there is no abnormality in the left-right swing, the maximum swing and the minimum swing. After the test run is smooth and no noise, it can be used normally.
