Investigation of effects on the contact condition and the collision behaviour of a wheelset with a flat set on a roller rig by the shape at the edge of the wheel flat

Abstract

We firstly executed bench tests of a bogie having the wheelset with a wheel flat installed on the roller rig. A wheel flat of 75 mm was prepared on the wheel tread and the front edge of the wheel flat was rounded by the grinding work. By making the radius of the front edge large, the maximum vertical acceleration of an axlebox decreased in the speed range less than 50 km/h compared with the one in case of the smaller front edge radius. The speed corresponding to the peak value of the maximum vertical acceleration of the axlebox shifted from 30 km/h to 80 km/h. Moreover, the peak value of the maximum vertical acceleration was larger than the one in case of the wheel flat edge without grinding work. To grasp and clarify the mechanism of the collision of the rotating wheel against a roller rig after descent leaving the roller rig, we built a simulation model and validated it by comparing the simulation results with the experimental ones, and the following were shown. The expansion of the radius r1 of the front edge of the wheel flat resulted in shitting of the spot of leaving the roller rig to the front side away from the front edge of the wheel flat. The shifting of the spot to leave the roller rig ahead makes the rear edge of the wheel flat collide against the roller rig at high speed, and then, a larger impact force is generated. Larger edge radii of r1=r2=429 mm nearly to the wheel radius, however, have the remarkable effect on decreasing the vertical acceleration of axleboxes in the whole operating speed range.

Keywords

• edge of the wheel flat
• edge radius
• front edge
• bench test
• simulation model
• shifting of the spot
• geometrical figure