Electric single-girder crane traveling Common Problems

Electric single girder  hoist crane  is widely used in various fields of national economy and sectors, is a modern large-scale industrial production of indispensable equipment. Affecting the electric single-girder crane use and personal safety equipment carts gnawing Road extremely common phenomenon, thus solving the problem of eating road, the maintenance of good, good use of the crane is especially important.

The so-called channel is eating or lifting trolley bridge crane during operation, the wheel rim and the side rails have squeezed bearing and friction, also known as gnawing rail.

Crane gnawing Road horizontal lateral force generated by the  gantry crane  rails, wheels, metal structures and structural frame beams will have a devastating effect, eating road level lateral forces caused by the following formula:

Ps = 1 / 2ΣP × λ

Where ΣP - Crane lateral forces occur most often on one side of the wheel pressure of unfavorable

λ - horizontal lateral force coefficient, with the crane span and gauge, generally take 0.1 to 0.2

Crane eating tract are complex, eating road damage took various forms. But can be summarized in the following aspects.

1. Orbit. Inspection found that many units do not meet the quality carts rail mounting requirements, rail fastening methods unscientific specification. First track appear wavy, exceeding the national standard gauge. Inspection rules of order: gauge S ≤ 10m, then the limit deviation ΔS = ± 3mm, S> 10m, ΔS = ± [3 +0.25 (S-10)] mm, the maximum does not exceed ± 15mm. Secondly, the fixed rail platen does not meet the requirements, were found in the metal structure housing frame more and more, more and more steel girder rail, fixed rail platen is fixed by simply bending iron, greatly reducing the pressure plate in horizontal and vertical directions of the tightening force, while the  jib crane  is in use will have a greater impact and vibration. Therefore, can not effectively prevent the plate, track move. Finally, the two orbital height difference is exceeded, if the same section of track height difference between two super abroad standard requirements, the crane runtime tilted to one side, causing gnawing road. Provides the same section should not exceed the height difference between two tracks 10mm. However, the actual testing, found because of the terrain, the layout and installation causes track rail mounting height difference exceeds the required range, the are not allowed.

2. Big Wheel horizontal and vertical deflection caused by excessive eating road. The horizontal deflection of the wheel shall not more than L/1000 (L is the measured length), if the width of the center line of the wheel beyond the standard centerline of the track forming an angle α, the driving wheel in the same direction if the two deflection, the wheel will follow the the direction of orbital angular deviation α running wheels inevitably chew road. Vertical deflection beyond the standard wheels also cause eating Road, wheel mounting face of the vertical deflection when not more than L/400 (L is the measured length). Deflect the wheel vertical centerline of the wheel tread forming an angle with the vertical line β, vertical deviation tolerance increased operating radius of the wheel, the original run of radius R, the wheels are the way to go run a week is 2πR, After generating a vertical deflection, which runs into the radius R1, run a week at this time the wheels are the way to go for the 2πR1, multiple runs per week running wheels 2πR1-2πR = 2π (R1-R) away, that is, for the wheels of the lead volume, but there are restrictions on the rim and not excessive lead track, resulting in gnawing round. Wheel vertical deflection caused by excessive eating, although only with the active channel vertical deflection on the wheel, and passive wheel has nothing to do, but even by force and wheel bearing wheel and rail contact surfaces other factors to consider, but also allowed the vertical deflection passive wheels out of tolerance.

Were found in the one hand, the crane during the manufacturing process, not the release of internal stress bridge, the bridge memory, the larger the residual stress, the actual use of the crane bear larger and complex environmental impact, or even illegal operations, the bridge in the course of stress release tray with varying degrees of deformation, resulting in horizontal and vertical deflection of the wheel causes excessive eating, and also the main reason for the crane gnawing Road. The other hand, the horizontal and vertical deflection installation error exceeds requirements lead to eating road. For this reason, in the processing and installation crane, on the one hand to minimize residual stresses and horizontal and vertical deflection amount; plus hand wheel deflection using a reasonable combination to counteract the runtime deviations.

The same set of wheels (active or passive) to be taken of the vertical deflection direction opposite arrangement, i.e. both inwardly deflected outwardly or both, so that when the bridge bearing, the wheel will reduce the amount of vertical deflection.

3. Transmission errors caused by crane operation gnawing road. For each driver traveling mechanism, if the motor is not synchronized, two tone elastic brake uneven road leading crane traveling bite for kinds of situations can be adjusted or replaced transmission parts, reducing the transmission error to solve and ultimately achieve synchronous operation.

4. Machining errors caused by the crane installation time eating road. Such as cranes carts two driving wheel diameter machining error is exceeded, or to avoid eating road, crane driving wheel tread processed into certain tapered so that the crane can be adjusted automatically at runtime, but if installed wrong direction arranged, will exacerbate the crane eating road.

In short, causing the crane eating tract of many factors, but simply by eating tract manifestations careful analysis of the scientific method and the steps taken, the problem is solved gnawing rail.