NVH issues of automotive brake pads

Abstract

Brake pad noise is not an isolated pad problem but relates to the whole brake assembly. The article groups the causes into three: the pad does not match the mating disc or drum; the pad has low stability with too-high impurity content; and, as specific pressure, temperature and speed change during braking, the pad and its mate adhere to each other.

The article calls the second cause the hardest to solve. A wear-resistant, moderately hard, noise-free pad needs high porosity together with heat resistance and durability; an unstable pad with severe fade will slide at high temperature, generate noise and wear fast. Its first recommendation is to remove raw materials with too-high impurity content — such as unprocessed minerals like pyrite — because impurities set the weakest link of the recipe, and sudden friction-coefficient drops also track high-impurity materials. High-quality metal sulfides are described as solving the recipe's weakest link, protecting the resin, stabilising the friction coefficient and slowing fade.

Key facts

• Cause 1: pad not matched to the mating disc/drum
• Cause 2: low pad stability, high impurity content — called the hardest to solve
• Cause 3: mutual adhesion between pad and mate as specific pressure, temperature and speed vary
• Recipe view: high porosity, heat resistance and durability needed for low wear, moderate hardness and low noise
• Impurity note: unprocessed minerals such as pyrite set the weakest link; sudden friction-coefficient drops track high-impurity raw materials
• Additive view: high-quality metal sulfides protect the resin and stabilise the friction coefficient

The original article is in Chinese; see the Chinese version for the full text. This page provides the English title, abstract and key facts only — translated and compiled from the original, without full verbatim translation.