Common failure causes and solutions of bridge crane brakes

The brake of the double-beam bridge crane is generally installed on the shaft of the motor to brake the operation of the motor, so that its operation or lifting mechanism can be accurately and reliably stopped at a predetermined position. The mechanism is braked through the principle of friction. When there is a problem with the brake, it needs to be adjusted and overhauled. The adjustment of the brake includes three aspects: adjusting the working stroke, adjusting the braking torque, and adjusting the braking gap. The editor of our factory introduces the causes of common failures of under-bridge crane brakes and the solutions to various failures.

1. The brake wheel cannot be braked (the heavy object slides down )

Causes:

1. The hinge of the lever is stuck
2. There is oil stain on the brake wheel and friction plate
3.  The electromagnet core does not have enough stroke
4.  The brake wheel or friction plate is severely worn
5.  The main spring is loose and damaged
6.  The lock nut is loose, the tie rod is loose
7.  The impeller of the hydraulic push brake does not rotate well

Solution:

1.  Clear the stuck fault
2.  Clean oil stains
3.  Adjust the brake
4.  Replace the friction plate
5.  Replace the friction plate
6.  Tighten the lock nut
7.  Overhaul the drive mechanism and electrical parts

2. The brake is not released

Possible causes of failure:

1.  The solenoid coil is burned out
2.  The wire leading to the electromagnet is disconnected
3.  The friction plate is stuck on the brake wheel
4.  The living hinge is stuck
5.  The main spring force is too large or the counterweight is too large
6.  The brake ejector rod is bent and the electromagnet cannot be pushed (on the hydraulic push rod brake)
7.  Improper use of oil
8.  The impeller is stuck
9.  The voltage is lower than 85% of the rated voltage, and the electromagnet is insufficient

The solution of the fault:

1.  Replace
2.  Connect the line
3.  Wash with kerosene
4.  Eliminate jamming and lubricate
5.  Adjust the main spring force
6.  Straighten the ejector rod or replace the ejector rod
7.  Change the oil according to the working environment temperature
8.  Adjust the push rod mechanism and check the electrical part
9.  Find out the cause of voltage drop and troubleshoot

3. The brake heats up, the friction plate emits a burnt smell and wears quickly

Possible causes of failure:

1.  After the brake shoe is released, it is not evenly disengaged from the brake wheel, resulting in friction
2.  The gap between the two brake shoes and the brake wheel is uneven, or the gap is too small
3.  The auxiliary spring of the short-stroke brake is damaged or bent
4.  The working surface of the brake wheel is rough

The solution of the fault:

1.  Adjust the gap
2.  Adjust the gap
3.  Replace or repair auxiliary spring
4.  Turn the brake wheel surface as required

4. The brake is easy to leave the adjustment position, and the braking torque is not stable enough

Possible causes of failure:

1.  The adjusting nut and back nut are not tightened
2.  Thread damage

The solution of the fault:

1.  Tighten the nut
2.  Replace

5. The electromagnet generates heat or makes a noise

Possible causes of failure:

1.  The main spring force is too large
2.  The lever system is stuck
3.  The position of the armature and the iron core is not correct

The solution of the fault:

1.  Adjust to a suitable size
2.  Eliminate the cause of jamming and lubricate
3.  Scrape the bonding surface

6. Common faults and problems of brake parts

1.  There are fatigue cracks on the tie rods
2.  There are fatigue cracks on the spring
3.  The wear of the small shaft and the mandrel reaches 3%～5% of the nominal diameter
4.  The wear of the brake wheel reaches 1～2mm, or the thickness of the original wheel rim is 40%～50%
5.  The friction lining of the brake shoe wears up to 2mm or 50% of the original thickness

Possible consequences

1.  Brake failure
2.  Brake failure
3.  Can't hold the brake
4.  Lifting down or rolling down the truck
5.  Brake failure

Solution

1.  Replace
2.  Replace
3.  Replace
4.  Re-turning, heat treatment, after turning, ensure that it is more than 50% larger than the original thickness. 40% of the brake wheel wear in the lifting mechanism should be scrapped
5.  Replace the friction plate

When there is a problem with the bridge crane brake, it must be repaired in time, and if the parts reach the scrap standard, it must be scrapped in time to avoid the production accident of the enterprise due to untimely repair.

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