Comparing load conditions of plane and false-ellipse running surface contours of track links in running gears for construction equipment

To improve durability and fatigue strength, it is advisable to give running surfaces of track links in undercarriages for construction equipment a false-ellipse profile. Such a profile resembles the contour of a running surface of a railway rail. Kinematic conditions as they exist for the track run in the undercarriage of construction equipment can however not be compared with those of a railway. Moreover, construction equipment in field operation is in particular faced with problems like lateral inclinations and misalignments between running surfaces of track link and bottom roller. For all this it is necessary to have a look at the load conditions of track links. This article makes clear that, above all with a view to the fact that in the past only plane running surface profiles were used for construction equipment applications, designing track link running surfaces with a false-ellipse profile has considerable advantages compared to plane running surfaces even at a misalignment ratio of just 1/5 of the maximum width of track link running surface.

► Theoretically line contact between links and rollers results in lowest loads.
► Links with false ellipse surface and cylindrical rollers result in point contact.
► Considering misalignment point contact proves to be less critical than line contact.
► It is advisable to give running surfaces of track links a false-ellipse profile.