Crane in the use of the process, mechanical parts, components, electrical control and hydraulic system components, inevitably follow the law of wear visible wear, and cause failure. The cause of the same failure may not be a one-to-one relationship. Therefore, it is necessary to analyze the fault carefully, find the real fault cause accurately, and take the corresponding method to eliminate the fault, so as to restore the technical performance of the fault point. Crane parts, components, electrical equipment and metal structure of the common failures and troubleshooting methods are listed in, the first chapter: crane faults and eliminate (parts), the second chapter: crane faults and eliminate (parts), the third chapter: crane faults and eliminate (electrical equipment), the fourth chapter: crane faults and eliminate (control and line section), the fifth chapter: crane troubleshooting (metal structure parts).
Chapter 1: crane failure and troubleshooting (parts)
I. failure and damage of forging hook:
1. Fatigue cracks appear on the surface of the hook. 2. Wear of openings and dangerous sections. 3. Plastic deformation occurs at the opening and bending parts.
Causes and consequences: 1. Overload, overdue use, material defects. 2. In severe cases, it weakens the strength, easily breaks the hook and causes accidents. 3. Long-term overload and fatigue.
Elimination method: 1. Crack is found and replaced. 2. Replace if the wear exceeds 10% of the dangerous section. 3. Replace immediately.
Ii. Failure and damage of laminated hook (plate hook) :
1. Hook deformation. 2. Fatigue cracks on the surface. 3. Pin wear exceeds 3% ~ 5% of nominal diameter. 4. Earrings are cracked or burred. 5. Ear ring bushing wear up to 50% of the original thickness
Causes and consequences: 1. Long-term overload, easy to break the hook. 2. Overdue, overload and damaged hook. 3. Hook comes off. 4. Broken earrings. 5. Poor stress condition
How to eliminate it: 1. Replace it. 2. The replacement. 3. The replacement. 4. Replace. 5. Change.
Iii. Failure and damage condition of wire rope
1. Broken wires, broken strands, knotted and worn.
Causes and consequences: 1. Sudden rope break.
Elimination method: break, knot stop using, broken wire, replace according to the standard, wear, replace according to the standard.
Iv. Pulley failure and damage:
1. Uneven wear of pulley groove. 2. Pulley mandrel wear up to 3% ~ 5% of nominal diameter. 3. The pulley won't move. 4. The pulley is inclined and loose. 5. Pulley crack or rim fracture.
Causes and consequences: 1. Uneven material, improper installation, poor contact between rope and wheel. 2. Broken mandrel. 3. Increased wear of mandrel and wire rope. 4. The positioning parts on the shaft become loose, or the wire rope jumps. 5. Pulley damage.
Elimination methods: 1. The wheel groove wall wear up to 1/10 of the original thickness, radial wear up to 1/4 of the rope diameter should be replaced. 2. The replacement. 3. Cleaning and maintenance. Enhance lubrication. 4. The positioning parts on the shaft become loose, or the wire rope changes to another job for maintenance. 5. Change.
Iv. Drum failure and damage:
1. Drum fatigue crack. 2. Wear of reel shaft and key. 3. Drum rope job-hopping wear and rope job-hopping, wear up to the original wall thickness of 15% ~ 20%.
Causes and consequences: 1. Drum broken. 2. The shaft is cut, causing the weight to fall. 3. The reel is weakened and easy to break; The wire rope was tangled.
Elimination methods: 1. Change the drum. 2. Stop using and immediately check and repair the shaft keys. 3. Replace the reel.
V. gear failure and damage:
1. Broken gear tooth. 2. Gear wear reaches 15% ~ 25% of original tooth thickness. 3. Gear crack. 4. The gear keyway is damaged due to "key rolling". 5. The spalling surface of the tooth surface accounts for 30% of the total working area, and the spalling depth reaches 10% of the tooth thickness; Carburized gear carburized layer wear 80% depth.
Causes and consequences: 1. Shock and vibration occur when working, continue to use damaged transmission mechanism. 2. Vibration and abnormal sound during operation are caused by overdue use and incorrect installation. 3. Gear damage. 4. Cause the crane to fall. 5. Quality problems of extended use and heat treatment.
Elimination method: 1. Replace the new gear. 2. Replace the gear. 3. The lifting mechanism should be replaced and the operating mechanism repaired. 4. The lifting mechanism should be replaced, and the operating mechanism can be newly processed and repaired. 5. Change. Speed reducer with peripheral speed >8m /s should be replaced in pairs when high-speed gear is worn.
Vi. Transmission shaft failure and damage:
1. The crack. 2. Shaft bending exceeds 0.5mm/m. 3. The key seat is damaged.
Causes and consequences: 1. The shaft was damaged due to poor material and improper heat treatment. 2. Cause wear of shaft neck, affect rotation, and generate vibration. 3. Unable to transfer torque.
Elimination method: 1. Replacement. 2. Replacement or correction. 3. The lifting mechanism should be replaced, and the operating mechanism can be repaired and used
Vii. Failure and damage condition of operating wheel set:
1. Fatigue crack on tread and spoke disc. 2. Uneven wear of active wheel tread. 3. Tread wear reaches 15% of wheel rim thickness. 4. Flange wear reaches 50% of the original thickness
Causes and consequences: 1. Wheel damage. 2. Causes the wheel to gnaw the rail, the car body to tilt and produces vibration when running. 3. Wheel damage. 4. It is easy to derail due to the tilt of the car body and the wheel gnawing on the track.
Elimination method: 1. Replacement. 2. Replace in pairs. 3. The replacement. 4. Replace.
Viii. Fault and damage condition of hydraulic brake
1. Fatigue crack on the tie rod. There are fatigue cracks on the spring. 3. Wear of small shaft and mandrel reaches 3% ~ 5% of nominal diameter. 4. Brake wheel wear amount is up to 1 ~ 2mm, or original flange thickness is 40% ~ 50%. 5. Brake tile friction plate wear up to 2mm.
Causes and consequences: 1. Brake failure. The brakes don't work. 3. Can't hold the brake. 4. Slide or slip the load. 5. Brakes don't work.
Elimination method: 1. Replacement. 2. The replacement. 3. The replacement. 4. After re-turning and heat treatment, it is guaranteed to be more than 50% of the original thickness. Brake wheel wear in lifting mechanism up to 3 or 50% 40% of original thickness should be scrapped. 5. Replace the friction plate.
Failure and damage condition of coupling:
1. Half body of coupling has cracks. 2. Coupling bolt and pin hole wear. 3. Tooth wear or broken tooth of tooth coupling. 4. Key seat crushing and deformation. 5. Wear of pin shaft, pin, rubber band, etc.
Causes and consequences: 1. The coupling is damaged. 2. Impact and vibration, bolt shearing and lifting mechanism are easy to occur when braking. 3. Lack of lubrication, heavy work, hit the car. Coupling damaged. 4. Release, unable to transfer torque. 5. Strong impact and vibration during braking.
