Design and Concept of a Tire Bead Separator Machine: Integrating a Two-Stage Shredding Process for Crumb Rubber Production

The mechanical process for tire recycling is crucial to reduce the pollution generated by waste tires. Furthermore, the resulting crumb rubber material can be used for synthetic grass courts and as an additive in road paving, among other applications. In this work, a tire bead separator machine is designed, and a two-stage shredder machine is proposed. First, an evaluation of the types of shredder machines is conducted, leading to the proposal of a primary shredding machine of dual-shaft type with a five-hook blade and a secondary shredding machine with a single-hook blade. Second, based on the loads that act on the shaft of the bead separator machine, a Von Mises stress of 134.05 MPa is determined. A safety factor of 2.61 is designed according to the yield strength of the shaft material and the calculated diameter of 50 mm. Thereafter, using the maximum torsional load acting on the shaft, 1500 Nm, it is found that the required electric motor power is 14 HP. A simple control and electric schematic diagram is proposed. Additionally, the stress calculations are verified using static simulations, resulting in the same maximum normal stress, shear force, and bending moment. Finally, a static simulation of the supporting structure revealed that the maximum deflection and stress are 0.27 mm and 42 MPa, respectively.