The Application of Mineral Fibers in Brake Shoes Production
In the production of brake shoes, the selection of appropriate materials for brake shoes friction materials is of utmost importance. Mineral fibers have become a key component in brake shoes mixtures and mixes, bringing both advantages and disadvantages to the table.
Advantages
- High – Temperature Resistance
- Mineral fibers exhibit remarkable high – temperature resistance. During braking, brake shoes are subject to intense heat. Tests have shown that brake shoes with 12 – 18% mineral fibers can maintain their structural integrity up to temperatures of around 600 – 700°C. In contrast, brake shoes without mineral fibers may start to degrade at temperatures above 400°C. This high – temperature resistance ensures that the brake shoes can function effectively even under extreme braking conditions, reducing the risk of brake fade.
- Improved Mechanical Strength
- They significantly enhance the mechanical strength of brake shoes. brake shoes mixes containing mineral fibers have been found to have a 30 – 40% increase in tensile strength compared to those without mineral fibers. For example, in a mechanical stress test, the brake shoes with mineral fibers could withstand a tensile force of up to 8000 N, while the non – mineral – fiber – containing ones could only endure 5000 N. This increased strength allows the brake shoes to better withstand the mechanical forces exerted during braking.
- Enhanced Friction Performance
- Mineral fibers contribute to enhanced friction performance. The friction coefficient of brake shoes with mineral fibers can be maintained at a relatively stable value of 0.35 – 0.45 under different braking speeds. In contrast, brake shoes without mineral fibers may experience a larger fluctuation in the friction coefficient, which can lead to inconsistent braking forces. This stable friction coefficient ensures smooth and reliable braking.
Disadvantages
- Environmental Concerns
- Mineral fibers, especially some types like asbestos – containing mineral fibers (although their use is being phased out due to health risks), can pose environmental problems. When brake shoes wear out, these fibers can be released into the air. Studies have shown that in an area with a high density of vehicles using mineral – fiber – containing brake shoes, the concentration of airborne mineral fibers can reach up to 0.1 – 0.3 particles per cubic centimeter, which may cause long – term environmental pollution and potential health hazards.
- Cost Factor
- High – quality mineral fibers can be relatively expensive. The cost of obtaining and processing certain types of mineral fibers can increase the production cost of brake shoes by about 20 – 30%. For example, some specialty mineral fibers sourced from specific regions require complex extraction and purification processes, making them a costly addition to brake shoes mixtures. This cost increase may be passed on to the consumers, affecting the market competitiveness of the brake shoes.
In summary, mineral fibers have distinct advantages in terms of high – temperature resistance, mechanical strength improvement, and friction performance enhancement in brake shoes production. However, their environmental concerns and cost implications need to be carefully addressed to make the most of their potential in the manufacturing of brake shoes friction materials.