1. Remove the largeslewing bearing

(1) Removal process

After the top door is fixed, use two 5t chain block, 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 holes on the anchor bolts to adjust and stretch the gap on both sides. Before stretching, lift it using a screw jack and 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 gap on both sides and the gap of the pinion for pulling out. When pulling to the half position, hang the special rope buckle for hoisting.slewing bearingAfter pulling to the hoisting position on the rack, command the door crane driver to hoistslewing bearing.

(2) Install newslewing bearingthe process

Before installation, pay attention to clean the newslewing bearing, Add grease and block the oil passage cavity with the oil filling hole. Before hoisting, lift the large slewing bearing 200mm from the ground for horizontal adjustment, so as to keep the large slewing bearing in a horizontal state and avoid sliding on the support. To avoid shearing the base, add a small amount of lubricating oil to the base. After stretching in place, use the four lifting lugs in the cylinder to adjust the largeslewing bearingAfter the bolt holes are aligned, prepare the installation surface for processing.

2.slewing bearingProcessing and cleaning of installation surface

Install newslewing bearingClean and measure the upper and lower flange surfaces before. The measurement process is as follows: each diagonal person holds a thin steel wire rope, selects the high point on the diameter as the reference point, and measures the sag of other points on the same line with a feeler gauge. The size of the limit large feeler gauge that the non-contact steel wire can be put into the gap is the sag, and the data of at least eight points of two straight lines perpendicular to each other are measured.

After measurement can be installed newslewing bearing. If the upper flange surface is processed after the new slewing bearing is in place, it is necessary to adjust the relative flatness of the upper joint surface of the slewing bearing and the upper flange surface, and then adjust the output pinion of the rotating motor. The tooth surface of the pinion can be combined with the tooth surface of the large ring gear by 1/3. If the two pinions interfere, remove one of the pinions, send high-voltage electricity to the gantry crane, and rotate in 1st gear to see if there is radial movement or play. The small tool holder can only be installed after it is stable. The flatness of the tool holder and the rotary bearing should be accurate, and the machining accuracy of the upper flange surface can be guaranteed within 0.2mm.

3. Demolition insurance decentralization process

After processing, cut the slewing support frame and windshield, etc. After the channel steel is cut in the reverse position, it can be polished with an angle grinder to place the reverse support. The descending process of the door crane is the reverse operation of the jacking process, and the operation process needs to obey the unified command of the same commander. Each descent process must be measured and adjusted within 50mm to ensure that the four-point error is within 5mm, and the door machine can only descend after a reverse gear. Before the bolts are fully placed in place, punch all the bolts in place and adjust the position of the slewing support so that the bolts are not subject to shear forces.

4. Bolt tightening process

After the slewing bearing is completely in place, hold the upper and lower nuts of the stud by hand to ensure that at least 3 buckles are exposed, and add high-strength flat pads under the nuts. Spring cushions are strictly prohibited. After adjusting the positioning of the slewing bearing, use a torque wrench to pre-tighten it three times in low, medium and high levels, and tighten it symmetrically in the direction of crossing 180 degrees. The steps shall be carried out in accordance with the instruction 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 the 10.9-grade bolt is 665kN.

5. Commissioning

After installing accessories, such as slewing bearings, intermediate slip rings, electrical and centralized lubrication, oil pan, pinion, etc. The large slewing bearing shall be oiled for trial operation. Test run with 1st gear rotation, check the meshing of the tooth surface, listen to see if there is any 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 bearing and the flange surface is less than 0.2mm. Test 2nd and 4th gears again to confirm that there is no abnormality in left and right swing, extreme large and extreme small swing. After the trial run is smooth and noise-free, it can be used normally.