crane translation mechanism problem

crane translation mechanism problem

Crane Translation Mechanism Problem–Running Out of Sync

Fault characteristics: The trolley twists or swings forward when starting or running, or the wheels show signs of climbing the rails when the trolley is running.

Phenomenon 1: The trolley is not synchronized when starting, but is synchronized when running

Fault cause

This phenomenon is caused by electrical faults, such as broken wires inside resistors, loose resistor wiring, damaged control points of controllers, etc.

Treatment measures:

1. After the resistor is broken, if the degree of broken wire is light, it can be welded together. If it cannot be connected well, the resistor should be replaced. If there is no problem with the resistor selection, the resistor wire will not break easily. Therefore, after the treatment, a comprehensive inspection should be carried out, such as whether the resistor line is connected incorrectly, whether the operation often relies on reverse braking to increase the heat, whether the on-site use conditions greatly exceed the working system of the crane, etc.

2. The resistor wire should be tightened if it is loose, and the other line connections should be fully inspected and tightened.

3. If the control point of the controller is damaged, it should be replaced in time.

Phenomenon 2: The trolley is always out of sync during startup and operation

Cause

This phenomenon may be caused by electrical faults, such as broken cores, missing phases, loose bolts, motor damage, or mechanical faults, such as increased resistance due to bearing damage of the drive mechanism at one end, or serious wear of the inner and outer teeth of the coupling at one end due to lack of oil, resulting in failure to drive, different speed ratios of the reducer, or different sizes of the two motors but the nameplates are mistakenly the same, and for three-in-one reducers, the number of teeth of the connecting gears between the motor and the reducer is different, etc.

Solution

1. First, we need to understand whether the car is newly installed or has been used for a period of time. If it is a car that has been used for a period of time, we need to understand when the fault occurred.

2. If it is a newly installed car, in many cases it is caused by circuit wiring errors. First, we should check the resistor circuit. If there is no problem with the electrical circuit, we need to check the mechanical aspects. First, we should measure the stator and rotor currents of the two motors. If the error is obvious, it can be judged that the motor has quality problems, or it is not the same model of motor but the nameplate is the same. If there is no problem with the motor, then we can check whether the speed ratio of the reducer is the same. Secondly, for the three-in-one reducer, we need to check whether the number of teeth of the connecting gear between the motor and the reducer is the same.

3. If the car has been used for a period of time and this fault has not occurred before, then check whether the sound of the drive mechanism is normal, whether the bearing is damaged, and whether the inner and outer teeth of the coupling are worn out. In terms of electricity, check whether the stator and rotor cables of the motor are broken, phase-lost, and loose, and take corresponding measures.

Improvement measures

For the quality problems of the product itself, the company should increase the quality inspection and management efforts. For problems during installation and use, it is recommended to hire an installation team with installation qualifications for installation. For problems arising during use, it is recommended that the user unit strengthen the daily work of use and maintenance.

The “three legs” of the trolley

Fault characteristics

If one wheel is suspended on the partial or full track, it will cause the trolley to twist and slide on the track when starting or twist and swing when stopping. The consequences are that the trolley drive shaft may be broken, the wheels may bite the rails, the wheel rims may wear, and the trolley may derail.

Causes of failure

1. When the trolley is manufactured and assembled, the wheels are not on the same plane, which will cause the trolley to have three legs throughout the journey.

2. The diameter of one of the four wheels is too small.

3. The trolley has been deformed for some reason: such as being hit during transportation, not slowing down when driving to the limit, and often stopping by hitting the stop.

4. Transportation, hoisting, long-term overload operation or harsh use environment (such as a large number of heat sources in the workshop and no insulation board at the bottom of the main beam, resulting in uneven heat deformation of the two main beams, causing deformation of the main beam of the trolley), resulting in a large local position difference between the two tracks, inconsistent main beam or track curves, which will cause the trolley to have three legs locally; the three legs of the trolley will cause twisting when starting.

Treatment measures

1. When the trolley is “three-legged” throughout the whole process, if the height of the driving wheel is “h”, the driven wheel diagonally opposite to the wheel can be adjusted, the driven wheel can be lifted up with a jack, and an adjustment pad of about “h” thickness can be added to the inner and outer corner boxes and the horizontal corner box of the wheel; if the driven wheel is suspended, the driven wheel can be directly lifted up, and an adjustment pad can be added to the inner and outer corner boxes and the horizontal corner box of the wheel; if the wheel is suspended more, a steel plate should be added between the key plate and the bent plate, and the key plate, steel plate and bent plate should be spot welded together.

2. When the trolley is partially “three-legged”, the height of the local track of the trolley should be adjusted, and the adjustment pad can be placed at the lower part of the track. It should be noted that the track pressure plate should be ground off with a grinder as much as possible to avoid or reduce the reduction of the main beam arch caused by heat deformation of the main beam caused by cutting off the pressure plate with gas cutting.

3. If the diameter is small, if it is a driving wheel, replace the wheel. If it is a passive wheel, add a gasket in the horizontal groove of the angular bearing box.