Analysis of the causes of jaw crusher failures and methods for troubleshooting

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I. Analysis of reasons for sudden shutdown of the main machine and methods for troubleshooting Reason analysis: 1. Blockage at the discharge port, resulting in material accumulation inside the machine； 2. The V-belt that drives the pulley is too loose, resulting in belt slippage ； 3. The retaining sleeve of the eccentric shaft is loose, resulting in no clearance on either side of the bearing housing in the frame; this causes the eccentric shaft to get stuck and be unable to rotate ； 4. The voltage at the work site is too low; the main unit lacks the power to crush large pieces of material ； 5. Bearing damage. Exclusion methods: 1. Remove blockages from the discharge outlet to ensure smooth discharge ； 2. Tighten or replace the V-belt ； 3. Reinstall or replace the retaining bushing ； 4. Adjust the voltage at the work site to meet the requirements of the main unit’s operating voltage ； 5. Replace the bearings. II. The main frame pulley and the moving jaw are operating normally, but analysis of the reasons for the cessation of crushing operation and methods to resolve it. Reason analysis: 1. The tension spring is broken ； 2. Rod fracture ； 3. Elbow plate detachment or fracture. Exclusion methods: 1. Replace the tension spring ； 2. Replace the tie rod ； 3. Reinstall or replace the elbow plate. III. Analysis of reasons why the output does not meet the factory standards and methods to resolve them. Reason analysis: 1. The hardness or toughness of the material being crushed exceeds the range specified in the user manual ； 2. The motor wiring is reversed, causing the main unit to operate in reverse direction (the moving jaw rotates clockwise), or the motor is connected in a star configuration instead of a delta configuration ； 3. The discharge port is smaller than the specified limit ； 4. The jaw plates are displaced, with the tooth tops facing each other ； 5. The voltage at the work site is too low ； 6. Excessive clearance resulting from wear of the moving jaw and bearings causes relative rotation of the outer ring of the bearings. Exclusion methods: 1. Replace or add a crusher ； 2. Swap the motor wiring ； 3. Adjust the discharge port to the nominal value specified in the manual, and add a crusher for fine crushing ； 4. Check the tooth pitch of the tooth plate; if it does not meet the standards, the jaw plate must be replaced. Adjust the relative position of the fixed jaw plate and the movable jaw plate to ensure that the tooth tips align with the tooth roots, after which the fixings should be tightened to prevent any displacement ； 5. Increase the voltage at the work site to meet the heavy-load requirements of the main machine. 6. Replace the bearings or the moving jaw. IV. Analysis of the reasons for vibrations or knocking sounds during the operation of the movable and fixed jaw plates, as well as methods to eliminate them. Reason analysis: 1. The fastening bolts of the jaw plates are loose or have fallen off ； 2. The discharge port is too small, causing the bottoms of the two jaw plates to collide with each other. Exclusion methods: 1. Tighten or secure the bolts properly ； 2. Adjust the discharge port to ensure the correct gap between the two jaw plates. V. Cause analysis and troubleshooting methods for elbow plate fractures Cause analysis: 1. The main engine is overloaded, or material larger than the size of the feed inlet enters ； 2. Non-crushing objects have entered the crushing chamber ； 3. The elbow plate and the elbow plate gasket are not parallel to each other; there is a skew ； 4. The castings have relatively severe casting defects. Exclusion methods: 1. Replace the elbow plates, control the feed particle size, and prevent the main machine from being overloaded ； 2. Replace the elbow plates and take measures to prevent non-breaking objects from entering the crushing chamber ； 3. Replace the elbow plates and the worn elbow plate gaskets, and install the elbow plates properly ； 4. Replace with qualified elbow plates. VI. Cause analysis and troubleshooting methods for spring breakage Cause analysis: The spring was not relaxed when the discharge port was adjusted smaller. Exclusion method: Replace the spring. VII. Analysis of the causes of seat breakage and methods for elimination. Cause analysis: 1. The elbow plates and elbow plate shims were purchased or modified independently, failing to meet the design requirements of the original equipment manufacturer ； 2. Loose fixing bolts of the adjustment seat ； 3. The adjustment seat has severe casting defects or welding defects. Exclusion methods: 1. Replace the adjustment seat and use the original elbow plates and elbow plate shims supplied by the manufacturer of the assembly machine ； 2. Replace the adjustment seat and tighten the bolts of the adjustment seat ； 3. Replace the adjustment seat. VIII. Analysis of the causes of eccentric shaft bending or fracture and methods for troubleshooting Causes: 1. The main machine tipped over during lifting, resulting in the eccentric shaft being bent due to uneven stress on one side ； 2. The hardness of the material being crushed exceeds the specifications stated in the product user manual ； 3. The host operates under excessive load for a prolonged period ； 4. The elbow plates do not meet the standards; they provide automatic shutdown protection when non-breakable objects enter the crushing chamber ； 5. Improper heat treatment of the eccentric shaft leads to stress concentration, resulting in fracture in a short period of time. Exclusion methods: 1. Replace with a new eccentric shaft, and lift the main unit properly ； 2. Replace with a new eccentric shaft; select an appropriate crusher based on the compressive strength of the material to be crushed ； 3. Replace with a new eccentric shaft, adjust the operating load, or replace it with a suitable crusher ； 4. Replace with a new eccentric shaft; do not use elbow plates or elbow plate shims that do not meet the design standards ； 5. Replace with a new eccentric shaft; use an eccentric shaft that has undergone proper heat treatment. IX. Cause analysis and troubleshooting methods for broken moving jaw Cause analysis: 1. Severe defects such as dense pores remaining from casting ； 2. The use of substandard elbow plates and elbow plate pads results in the absence of self-cutting protection for the crusher when subjected to strong impacts ； 3. The moving jaw shifts within the frame, with its bottom end hitting the frame’s side guard plate ； 4. The tie rod spring tension failed, yet it was not replaced in a timely manner ； 5. The discharge port is smaller than the specified limit ； 6. The feeding position is incorrect, skewed to one side, or the angle of the discharge hopper is too steep, causing the material to strike directly the head of the moving jaw. Exclusion method: 1. Replace the moving jaw. 2. Replace the moving jaw. At the same time, install the original elbow plates and elbow plate pads produced by the vehicle manufacturer ； 3. Replace the moving jaw. At the same time, properly assemble the eccentric shaft, bearings, retaining sleeves, and moving jaw, and replace any damaged parts ； 4. Replace the moving jaw. Replace the tie rod spring at the same time ； 5. Replace the moving jaw. Adjust the discharge port as required at the same time ； 6. Replace the moving jaw. At the same time, add feed hoppers to ensure even and steady material discharge, as well as distribution from the center to both sides. X. Cause analysis and troubleshooting methods for excessive temperature rise in the frame bearing housing or moving jaw. Cause analysis: 1. Lack of oil supply to the bearings or excessive oil injection ； 2. The oil holes are blocked, preventing oil from entering ； 3. The weight block of the flywheel is misaligned, causing the frame to vibrate ； 4. Axial movement of the retaining bushing occurs ； 5. Bearing wear or cage damage, etc ； 6. It is not the temperature rise of the bearings, but rather heat generated due to friction between the moving jaw seal sleeve and the end cover, or friction generated as the double-cover bearing housing of the frame rotates together with the main shaft. Exclusion methods: 1. Fill the fuel on time and in the prescribed amount as specified in the instructions ； 2. Clean blockages in oil holes and oil grooves ； 3. Adjust the position of the flywheel counterweight ； 4. Remove the bearing cover from the frame, lock the retaining sleeve, and remove the flywheel or sprocket; replace it with a new retaining sleeve ； 5. Replace the bearing ； 6. Replace the end cover and seal sleeve, or loosen the upper bearing cover at the end of the frame bearing housing that is overheating. Press the fuse together with the insert cover into the groove of the frame bearing housing, then reinstall the upper bearing cover to prevent the insert cover from rotating. XI. Analysis of the reasons for axial left-right swinging of the flywheel and methods to eliminate it. Reason analysis: 1. Wear of the flywheel hole, flat key, or shaft, resulting in loose fit ； 2. The stones get crushed against the inside of the wheel, causing cracks in the wheel housing ； 3. Casting defects ； 4. The tensioning sleeve of the flywheel is loose. Exclusion methods: 1. Wear of the flat key – replace the flat key, or replace the eccentric shaft or the flywheel ； 2. Add a protective cover for the flywheel and replace the eccentric shaft or flywheel ； 3. Replace the eccentric shaft or pulley. 4. Retighten the tensioning sleeve. XII. Cause analysis and troubleshooting methods for rack cracking Cause analysis: 1. Casting defects or welding quality defects ； 2. The use of substandard elbow plates and elbow plate pads resulted in the frame cracking due to the lack of self-shutting off protection for the elbow plates when the crusher was subjected to intense impacts ； 3. The fixed jaw plate is not secured, causing it to move up and down over time and collide with the toothed plate brackets on the front wall of the frame ； 4. Poor rigidity of the base feet of the main unit, excessive horizontal deviation or collapse, resulting in frame vibration ； 5. The two bolts on the frame bearing cover are loose ； 6. Continuing to use fixed and movable jaw plates after tooth wear ； 7. The direction of the counterweight block on the flywheel is misaligned due to damage to the eccentric shaft or pins, or because the tensioning sleeve is loose. Exclusion methods: 1. Remove the original crack defects, repair by welding, and replace the frame with a new one if necessary ； 2. Repair or replace the frame with a new one, and install the original elbow plates and elbow plate pads produced by the manufacturer of the main unit ； 3. Repair or replace the frame with a new one, and tighten the fixing tooth plate bolts ； 4. Repair or replace the frame with a new one, tighten the foot bolts of the frame, adjust its level, and reinforce the foundation ； 5. Repair or replace the frame with a new one, and tighten the two bolts on the bearing cover ； 6. Repair or replace the frame with a new one, and replace the jaw plate promptly when it becomes worn out ； 7. Repair or replace the frame with a new one, swap the pin shaft or adjust the orientation of the eccentric block, and tighten the expansion sleeve. 13. Analysis of the causes of knocking sounds at the rear of the frame and methods to eliminate them. Cause analysis: 1. The tie rods are not tightened properly, causing the elbow plates to strike the moving jaw as well as the elbow plate pads of the adjustment seat ； 2. There is friction between the pull rod and the hook at the lower part of the moving jaw ； 3. The spring and the spring seat collide with each other. Exclusion methods: 1. Tighten the tie rod ； 2. Check whether the spring tension has failed; if so, replace the spring, tighten the tie rod, or re-tighten the spring ； 3. Install the spring seat in place, and tighten the tie rod nut to the appropriate position. 14. Cause analysis and troubleshooting methods for severe frame vibration Cause analysis: 1. Loose or broken foundation bolts ； 2. The positions of the flywheel and cam weight blocks are offset ； 3. The foundation of the main structure is not solid, and there are no seismic isolation measures in place. Exclusion methods: 1. Tighten the anchor bolts or replace the broken bolts ； 2. Remove the end cover of the flywheel shaft, loosen the bolts that secure the flywheel and the pulley tensioning sleeve, adjust the positions of the flywheel and pulley counterweights, and then tighten the bolts of the tensioning sleeve ； 3. Reinforce the foundation by adding sleepers or rubber, etc.