Development of a Novel Magnetic Brake Shoe for Mine Hoists Based on Nano-Fe3O4 and Nd-Fe-B Additive

Background: The brake is an important safety protection device for mine hoists, in which the performance of the brake shoe affects directly the safe operation of the hoist system. In order to solve problems such as high wear rate and unstable friction coefficient of brake shoe under high temperature, this paper indicated that adding magnetic powder to the composite material of traditional mine hoist's brake shoe will be a creative and effective approach to improve its properties. Methods: Based on relevant China patents of the authors, several new formulas of brake shoe material were designed in the presence of Nano-Fe3O4 and Nd-Fe-B, and the methods of both preparation and performance testing of the magnetic brake shoes were introduced. The experiment of formula design was carried out by uniform prescription design, and the friction coefficient and wear rate of each kind of brake shoes made through different formulas were measured. Furthermore, the formula was optimized by application of fuzzy comprehensive evaluation method and analytic hierarchy process. Results: Compared with ordinary formulas, the optimized formula is higher totally and changes more steadily as well. Its wear rate is far lower than the national standard. Namely, its comprehensive properties are better. Few relevant patents to the topic have been reviewed and cited. Conclusion: This paper proved that it is practically valuable and feasible to improve the properties of hoist brake shoes by adding magnetic powder to its composite material.