The traditional drum track is with solid structure. It is very heavy, weighting about 250kgs. And it will be bigger when the concrete mixer drum capacity is larger. Because the track with solid structure is lack of the deformability, the welded track onto the drum often snaps when using for some time. If only reducing the sectional dimension of the track ring to reduce its weight, the rigidity of the track will be decreased a lot that it cannot bear the weight of the drum. So it is a big challenge for the engineer to reduce the weight of the drum track.
The new style track of TOPIVOT is with hollow structure. It can reduce the weight and the production cost of the track.
The hollow drum track ring is produced by entirely ring rolling. In the meanwhile, increasing the forging pressure, then by the process of repeatedly heating-blank making-post forming, so it can ensure the compactness of the structural constituent after forging. We use the special mold to make the hollow part by roll forging. Because the track is formed by repeatedly heating, the quality is much better than the traditional one.
When design the hollow structure track, the actual using conditions should be considered. When the mixer drum is full loaded, the center of gravity will move forward to the drum head. So the small side thickness of the track should be 3 to 5 mm more than the big side thickness to ensure the support stiffness for the full loading condition. And the height of the outside of the track is the same as before, so it will not influence the integral rigidity of the track.
Comparing with the traditional track, the hollow track ring has the following advantages:
1. The weight of the track can be reduced by 20%, about 30 or 40kgs. The cost can be reduced about by 15%.
2. Hollow structure can absorb some welding stress when the track is welded with the mixer barrel.
3. When welding the track with the mixer drum, because the contact surface is reduced, the positioning is easier.
4. Because of the hollow structure, if the track needs to be replaced, the drum track can be disassembled only by using the gas cutting and blowing the welding in the drum’s axial direction. But the traditional solid structure track doesn’t have the space for blowing and it’s difficult to be disassembled.
5. The hollow part of the drum track doesn’t have to be finish machining. It means that the finish machining surface of the drum track is reduced so as to reduce the machining time and increase the production efficiency.