Crane wheel forgings are a classification of forgings, mainly used in portal cranes, port cranes, bridge cranes, and mining machinery. The contour line formed by the flange and tread on the radial section of the crane wheel forging. The choice of the flange and tread shape of the crane wheel forgings not only affects the wear and service life of the crane wheel forgings on the track, but also directly affects the curve performance and running quality of the equipment. The rim allows crane wheel forgings to reliably pass through curves and turnouts without derailment.
The tread is conical, with a taper of 1:10 near the rolling circle. When passing the curve, the outer wheel rolls on the outer rail with a larger diameter near the rim, and the inner wheel rolls on the inner rail with a smaller diameter. In this way, on the one hand, the crane wheel forgings can guide as the line direction changes. The difference in wheel rolling distance can also compensate for the effect of the difference between the length of the inner and outer rails.
When running on a straight line, if the wheel pair deviates from its center position on the line, the difference between the rolling radii of the two wheels will cause the wheel pair to move in the direction of returning to its center position. The outer taper of the wheel is 1: 5, which can increase the difference between the rolling radius of the two wheels, making it easier to pass through the small radius curve. Decreasing the taper of the tread helps to suppress meandering motion, but the wear of the rim is significantly intensified, and the spin cycle and wheel life are greatly shortened. This approach is only used on some high-speed passenger trains.
The profile of the crane wheel forging rim tread wears quickly in the early stages of operation, and then gradually stabilizes and wears down. The shape after the spin repair cannot be maintained for a long time, and the amount of metal cutting is large. Therefore, the railways of some countries have adopted a profile of a wheel pair that is close to abrasion to a relatively stable state, called a concave tread, also known as a wear-shaped tread. Adopting this shape not only reduces wheel wear and prolongs the repair cycle, but also improves the contact state of the wheel and rail, which reduces contact stress.