Anti-slip serration design of rail bearing plates and rail lateral restraint
What are the specification requirements for the design parameters of national standard trapezoidal anti-slip tooth patterns?
The tooth depth of national standard trapezoidal anti-slip tooth patterns should be controlled at 0.8-1.2mm. If the tooth depth is too shallow, it cannot provide sufficient friction, and if it is too deep, it is easy to damage the surface of the rail web. The tooth width is set to 2-3mm, and the tooth spacing is 5-8mm. This parameter combination can ensure the anti-slip effect and avoid stress concentration at the tooth patterns. The inclination angle of the tooth pattern is 45°, which can maximize the decomposition of lateral loads, convert lateral forces into pressure perpendicular to the tooth surface, and improve the constraint effect. The machining accuracy of the tooth pattern is strictly required, and the roughness of the tooth top and tooth bottom should be ≤Ra3.2μm to prevent sharp edges from wearing the rail. In addition, the specification requires that the tooth pattern area must cover the main contact area between the pressure plate and the rail, with a coverage rate of not less than 70% to ensure the uniformity of the overall anti-slip constraint.
What are the advantages of foreign standard diamond-shaped anti-slip tooth patterns compared with trapezoidal ones?
Foreign standard diamond-shaped anti-slip tooth patterns have more contact points and form multi-point engagement with the rail, which can provide a more uniform friction distribution and reduce local wear. Its bi-directional anti-slip performance is excellent, which can resist the lateral displacement of the rail to the left and right at the same time, adapting to the bi-directional load working conditions of small-radius curves. The stress dispersion of diamond-shaped tooth patterns is better, and the diagonal design of the tooth patterns can transmit the load to a larger range, reducing the risk of stress concentration of the pressure plate itself and extending the service life of the pressure plate. The self-cleaning ability of the diamond-shaped tooth pattern is strong, and the sand and dust in the track can be discharged along the diamond gap, avoiding the failure of the tooth pattern due to sand accumulation. In addition, the processing of diamond-shaped tooth patterns can adopt one-time forming technology, and the production efficiency is 20% higher than that of trapezoidal tooth patterns, and the precision is easier to control.
Why is it necessary to strengthen the wear-resistant treatment of the anti-slip tooth patterns of pressure plates for heavy-haul lines?
The train axle load of heavy-haul lines is large, and the lateral friction between the pressure plate and the rail is 2-3 times that of conventional speed lines. If the wear resistance of the tooth pattern is insufficient, it will be quickly worn flat and lose the anti-slip constraint ability. Strengthening the wear-resistant treatment can increase the surface hardness of the tooth pattern to above HRC55, and its wear resistance is three times that of ordinary pressure plates, which can withstand long-term high-frequency friction loads. The wear-resistant treated tooth pattern can reduce adhesive wear with the rail and avoid corrosion of track components caused by metal debris generated by tooth pattern wear. The wear-resistant tooth pattern can maintain stable friction, ensuring that the lateral displacement of the rail is always controlled within 0.3mm and ensuring the stability of the line geometry. In addition, the wear-resistant tooth pattern can reduce the replacement frequency of the pressure plate, extending the maintenance cycle from 1 year to 3 years, and greatly reducing the operation and maintenance cost of heavy-haul lines.
What are the selection points of pressure plate tooth patterns in small-radius curve sections of urban rail?
Pressure plates in small-radius curve sections of urban rail need to adopt bidirectional anti-slip tooth patterns, and diamond-shaped tooth patterns are preferred to cope with the bidirectional lateral force when the train turns and prevent the rail from reciprocating lateral displacement. The tooth depth of the tooth pattern should be appropriately increased to 1.2-1.5mm, and the tooth spacing should be reduced to 4-6mm to increase the friction per unit area and resist greater centrifugal loads. The tooth pattern area of the pressure plate needs to be locally thickened, with the thickness increased by 2-3mm compared with the pressure plate in ordinary sections, to enhance the anti-deformation ability of the pressure plate and avoid plastic deformation of the tooth pattern due to excessive load. The tooth pattern material should be wear-resistant alloy steel, and the surface should be sprayed with tungsten carbide coating to further improve the wear resistance and impact resistance, adapting to the high-density operation conditions of urban rail. In addition, the tooth pattern must be compatible with insulating gaskets, ensuring the insulation requirements of electrified sections while preventing slipping and avoiding signal interference.
What are the on-site testing and maintenance points of the anti-slip tooth patterns of pressure plates?
When testing the anti-slip tooth patterns of pressure plates on-site, first use a depth gauge to measure the tooth depth. If the tooth depth is worn to less than 50% of the design value, the pressure plate must be replaced in time. Secondly, the anti-slip performance is tested with a friction tester. If the friction attenuation exceeds 20%, the tooth pattern is judged to be invalid. It is also necessary to check whether there are cracks and chipping on the surface of the tooth pattern, which will lead to stress concentration and cause the pressure plate to break. In daily maintenance, the sand and oil stains in the tooth pattern gaps should be cleaned regularly to maintain the occlusal state of the tooth pattern and avoid impurities affecting the anti-slip effect. For tooth patterns with light wear, local repair welding and reprocessing can be used to restore the anti-slip performance; for severely worn pressure plates, overall replacement is required to ensure the reliability of the lateral constraint of the rail.