Cranes are large-scale equipment and consist of many parts and components. In order to ensure the safe and balanced operation of the equipment, enterprises must do a good job in the maintenance of primary and secondary maintenance of crane equipment . The editor introduces the maintenance items and work content of each component of the crane.
(1) Disassemble and check the hooks, shafts, beams, pulleys, bearings and clean and lubricate them. The hooks, beams, pulley shafts are not allowed to have cracks, the threaded parts should not be loose, the bearings are intact, rotate the pulleys, and the threaded undercut grooves Those with knife marks or cracks should be replaced;
(2) Check the wear condition of the dangerous section, if the wear of the dangerous section exceeds 10% of the original height, replace it;
(3) The hook test. After overhaul, the hook should be tested and checked. The hook should be suspended for 10 minutes at 1.25 times the rated load. The elastic opening of the hook should not exceed 0.25% of the size of the hook, and there should be no permanent deformation after unloading. And cracks;
(4) The board hook is overhauled. After the board hook is riveted, the gap between the board and the board should not be greater than 0.3mm.
(1) Broken wire inspection: If the number of broken wires in a lay length exceeds 10% of the total number of steel wires, it should be scrapped according to the standard;
(2) Radial wear: If the radial wear of the steel wire exceeds 40% of the original diameter, the entire wire rope should be scrapped;
(3) Deformation inspection: the diameter of the wire rope is reduced to 70% of the kinks of the rope diameter, the core of the rope is exposed, and those with broken strands should be scrapped and replaced with a new wire rope;
(4) Steel wire rope lubrication: clean with wire brush, kerosene, etc. before lubrication, and use wire rope sesame grease (Q/SY1152-65) or synthetic graphite calcium-based lubricating finger (SYA1405-65) to dip and saturate it.
(1) Remove and repair the pulley block, check for cracks, the pulley shaft must not have cracks, the journal must not wear 30% of the original diameter, and the taper should not be greater than 5%. If it exceeds this value, it should be replaced;
(2) For the maintenance of the pulley groove, check the pulley groove shape with a sample plate. The radial wear should not exceed 30% of the wall thickness, or it should be scrapped. Those who cannot exceed the standard can be repaired. After major repairs, check with a sample plate. The bottom and lateral gaps should not be greater than 0.5mm. The deviation between the centerline of the wheel groove and the centerline of the pulley should not be greater than 0.2mm. The deviation should not be greater than 1mm;
(3) Inspection of the shaft hole, after overhaul, the shaft hole is allowed to have defects not exceeding 0.25CM2, and the depth should not exceed 4mm;
(4) After assembly, it should be able to rotate flexibly by hand, and the lateral swing should not exceed D/1000. D- the nominal diameter of the pulley.
(1) The rope groove of the reel, the rope groove should be re-machined if the rope groove wears more than 2mm. After the overhaul, the rope groove should meet the requirements of the drawing, but the wall thickness of the reel should not be less than 81% of the original thickness;
(2) The surface of the reel, there should be no cracks on the surface of the reel, there should be no obvious out-of-roundness, and the pressure plate screw should not be loose;
(3) There should be no cracks on the reel shaft and the reel shaft should meet the drawing requirements after major repairs. When the wear exceeds 5% of the nominal diameter, new parts should be replaced;
(4) For assembly and installation, the centerline of the reel shaft should be parallel to the support surface of the trolley frame, and the deviation should not be greater than 1mm/m. After the reel is installed, the deviation of the centerline of the two shaft ends should not be greater than 0.15mm.
(1) Wheel tread wear. When the wheel tread wear exceeds 15% of the original thickness, new parts should be replaced. If it does not exceed this value, it can be re-machined and repaired by heat treatment. The wheel diameter should be within the tolerance range, and the surface quenching hardness should be HB300~500. The thickness of the quenching layer of the wheel with a diameter greater than Φ400mm should be greater than 20mm; when it is less than Φ400mm, the thickness of the quenching layer should not be less than 15mm;
(2) The diameter deviation of two mutually matched wheels. The diameter deviation of the active wheel should not exceed 0.1% of the nominal diameter, the driven wheel should not exceed 0.2%, and the diameter deviation of the electric hoist wheel should not exceed 1% of the nominal diameter. The motor wheel should not exceed 0.2%; the wheel diameter deviation of the electric hoist should not exceed 1% of the nominal diameter; (3) Flange wear and breakage, deformation: Flange wear reaches 50% of the original thickness or the broken area exceeds 30mm2 should be scrapped , The rim thickness should be scrapped when the bending deformation reaches 20% of the original thickness;
(4) Wheel cracks: the wheel should be scrapped if cracks are found;
(5) Tread ovality: the wheel tread ovality of 1mm should be scrapped;
(6) Wheel assembly assembly: The installed wheel assembly should be able to rotate flexibly by hand. Several wheels installed on the same balance frame are in the same vertical plane, and the allowable deviation is 1mm.
(1) The overhaul of the journal: the ellipticity and conicity of the journal after the overhaul should not be greater than 0.03mm;
(2) Inspection and repair of cracks: check the shaft with magnetic or ultrasonic flaw detectors, there must be no cracks on the shaft, and the scratch depth shall not exceed 0.03mm;
(3) Overhaul of rolling bearings: Axial clearance in the range of 0.03~0.18mm is allowed between the inner and outer rings of tapered roller bearings. The adjustment gap of the bearing gland should be within the range of 0.5~1.5mm.
(1) Disassemble the reducer to clean and check the gear grinding condition;
(2) Tooth surface inspection: the wear of the gear on the first shaft of the reducer of the hoisting mechanism should not exceed 10% of the tooth thickness, and the rest should be less than 20%; Should exceed 15%, and the rest should be less than 25%. When the tooth surface pitting corrosion damages 30% of the meshing surface, and the depth reaches 10% of the original tooth thickness, the gear should be scrapped. There should be no cracks in the gear teeth or the gear should not have broken teeth. Otherwise replace;
(3) Maintenance of the shaft: there must be no cracks on the shaft, the total length of the shaft curvature should not exceed 0.03mm/m, and it will be straightened if it exceeds the standard;
(4) The joint surface (split surface) of the reducer box is not allowed to be smashed, bumped, severely scratched, edge high points, flanging, etc., and the gap after the split surface is fitted should not exceed 0.03mm , And ensure no oil leakage. Parallelism above 1m shall not be greater than 0.5mm;
Under no-load conditions, drag and run at 1000r/min, and the forward and reverse rotations should be no less than 10 minutes. When starting, the motor should not have vibration, impact, and violent or intermittent abnormal sound;
The temperature rise in the box should not exceed 70℃, and the absolute temperature should not exceed 80℃; the temperature rise of the bearing should not exceed 40℃, and its absolute value should not exceed 80℃.
(1) Tooth surface inspection and repair of gear coupling;
(2) Inspection of the swing amount of the inner and outer ring gear ends facing the centerline;
(3) When the center line of the shaft is not inclined, check the radial displacement of the coupling installation;
(4) When there is no radial displacement, check the skew angle of the outer ring line caused by the misalignment of the two couplings;
(5) The radial displacement of the gear coupling with the intermediate shaft.
(1) Overhaul of brake friction pads: the amount of wear should not exceed 50% of the original thickness, and the rivets should sink ≥2mm;
(2) Brake wheel maintenance: The roughness of the working surface of the brake wheel is not less than Ra=16μm, the HRC is not less than 50, and the depth of 2mm is not less than HRC40;
When the working surface dent or unilateral radial wear reaches 1.5mm, it should be re-machined and heat-treated.
The thickness of the brake wheel after processing: the lifting mechanism should not be less than 70% of the original thickness, and the operating mechanism should not be less than 50% of the original thickness. After the brake wheel is overhauled, the radial runout of D≤200mm should not be greater than 0.05m , The radial runout of D>200mm should not be greater than 0.1m.
(1) The shaft of the hoisting mechanism: check the main shaft and drive shaft of the hoisting mechanism by flaw detection, and no cracks are allowed;
(2) Displacement inspection of motor and reducer: it should meet the installation requirements of the coupling;
(3) The axis deviation of the reel and the reducer: the allowable deviation at the bearing seat should not be greater than 3mm/m;
(4) Trolley gauge deviation: due to the trolley gauge deviation measured by small wheels: when the gauge is ≤2.5m, the allowable deviation is ±2mm, and the relative difference between the driving and driven wheels is not more than 2mm, and when the gauge is >2.5m, it is allowed. The deviation is not more than ±3mm, and the relative difference of the driving wheel is not more than 3mm;
(5) Trolley track elevation deviation: when the trolley gauge is ≤2.5mm, the allowable deviation is 3mm; when the gauge is >2.5m, the allowable deviation is 5mm;
(6) Deviation of track centerline from the design centerline of rail beam: allowable deviation of box-shaped single beam: not more than 1/2δ, δ-web thickness (mm), allowable deviation of single web beam: not less than 10mm , The allowable deviation of the box-shaped double main beam is: 2~3mm;
(7) Trolley track joint deviation: the elevation deviation and centerline deviation at the track joint ≤ 1mm;
(8) The horizontal deviation of the end surface of the small wheel: the horizontal deviation should not be greater than 1/1000, and the main direction of the deflection of the two driving wheels is opposite, 1-measure the length;
(9) The deviation of the end face of the small wheel: not more than D/400;
(10) Small wheel tread deviation: all wheel treads must be in one plane, and the deviation should not be greater than 0.5mm;
(11) Small wheel track deviation: allowable relative deviation is 4mm.
11. Maintenance of operating mechanism of crane trolley
(1) Wheel deviation: the horizontal and vertical deviation of the wheel of the big car is the same as that of the small wheel;
(2) Inspection of wheels on the same balance beam: the symmetry planes of the two wheels on the same balance beam should be in the same vertical plane, and the allowable deviation should not be greater than 1mm;
(3) Track visual inspection: the track should not have cracks, the wear of the top of the track, the side of the track head, etc. should not exceed 3mm; the longitudinal inclination of the grúa de la pista should not be greater than 5/1000;
The relative elevation deviation of two tracks in the same section is ≤10mm;
(4) Overhaul of the rail clamp: if the jaw wear exceeds 40% of the original thickness, it should be replaced. The electric rail clamp should always pay attention to adjusting the safety ruler so that the pointer is at the specified position;
(5) Crane span deviation measured by wheels: when span L≤30m, span deviation should not be greater than 5mm, when L>30m, span deviation should not be greater than 8mm.
(6) Diagonal deviation measured by the wheel: when the span is less than or equal to 30m, the deviation should not be greater than 5mm, when L<30m, the deviation should not be greater than 10mm
Crane users should improve the maintenance system of crane equipment and regularly maintain cranes.
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