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(1) Place the paver on the flat ground, set the elevation value to zero, drop the ironing pull and place it on a flat loose sandstone layer. After several minutes, put forward the ironing plate. Observe the indentation of the front end of the ironing plate on the sandstone layer. If the indentation is obvious, it indicates that the ironing pull is in normal condition; if the indentation is not obvious or the indentation appears in the back, it indicates that the ironing plate has appeared to varying degrees. Wear. After many experiments, it was found that the indentation was not obvious, which indicated that the ironing plate had been worn. The elevation of the paving machine is higher than that of the new machine, which also explains this problem.

(2) In order to further explore the extent of wear and tear of the ironing plate (of course, the deformation of the arm of the ironing plate can also be checked out in extremely unexpected circumstances), the pads with thickness of 1mm, 2mm, 2.5mm and 3mm are added at the lower connection of the ironing plate and the lifting arm respectively to increase the original elevation angle of the ironing plate and observe the improvement of the failure respectively. It is found by experiments that the pads with thickness of 1mm, 2mm, 2.5mm and 3mm are added to the lower connection of the ironing plate and the After adding the gasket with the thickness of 2.5mm, no failure was found in the paving of medium-sized asphalt concrete, but the paving of fine-grained asphalt concrete still has the phenomenon that the thickness is difficult to control.

(3) Through the inspection of (1) and (2), it can be concluded that the failure phenomenon has nothing to do with the automatic leveling system, but has something to do with the wear of the ironing plate. Considering that the failure phenomenon is related to the condition of the asphalt mixture and the running speed, it should be suspected that the wear of the front rammer caused by the wear of the ironing plate bottom plate can lead to these failure phenomena. The frequency of rammer is lowered, but the effect is not obvious. The disassembly inspection found that the front rammer had been severely worn, and the relative position between the lowest ramming stroke and the bottom plate of the ironing plate changed greatly.

When the rammer is in the lowest position, it is higher than the bottom plate worn by the ironing plate, which results in the front of the ironing plate forming a denser "material block" through the vibration and tamping of the rammer during paver paving. The "material block" has a greater buoyancy on the ironing plate than under normal conditions, thus preventing the pressing "feed" of the ironing plate, and at the same time, the serious wear and tear of the ironing plate bottom plate is also increased. The difficulty of downward pressure is aggravated, which leads to the phenomenon that the thickness of the leveling cylinder has not decreased although it has reached the maximum stroke position. With the increase of paving speed, the compactness of the compacted "material block" will be reduced, and the compactness will also be reduced, thus returning to the normal working state. In addition, under the same compaction effect, the "material block" formed by fine-grained asphalt concrete is denser than that of medium-grained asphalt concrete, so the failure phenomenon is much more serious when paving fine-grained asphalt concrete. As for the failure of the right side of the ironing plate, it is because the wear of the front part of the right side of the ironing plate and the rammer is much worse than that of the left side (in this case, the ironing plate has worn into trapezoidal cross section, the front part of the left side is only about 3 mm, while the normal thickness is 16 mm, and the front part of the left side wears more normally, about 13 mm).