Common failure causes and solutions of bridge crane brakes

Table of Contents

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:

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

Solution:

Clear the stuck fault
Clean oil stains
Adjust the brake
Replace the friction plate
Replace the friction plate
Tighten the lock nut
Overhaul the drive mechanism and electrical parts

2. The brake is not released

Possible causes of failure:

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

The solution of the fault:

Replace
Connect the line
Wash with kerosene
Eliminate jamming and lubricate
Adjust the main spring force
Straighten the ejector rod or replace the ejector rod
Change the oil according to the working environment temperature
Adjust the push rod mechanism and check the electrical part
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:

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

The solution of the fault:

Adjust the gap
Adjust the gap
Replace or repair auxiliary spring
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:

The adjusting nut and back nut are not tightened
Thread damage

The solution of the fault:

Tighten the nut
Replace

5. The electromagnet generates heat or makes a noise

Possible causes of failure:

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

The solution of the fault:

Adjust to a suitable size
Eliminate the cause of jamming and lubricate
Scrape the bonding surface

6. Common faults and problems of brake parts

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

Possible consequences

Brake failure
Brake failure
Can't hold the brake
Lifting down or rolling down the truck
Brake failure

Solution

Replace
Replace
Replace
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
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.