Fibre selection points and formulation advice for drum brake shoes

Abstract

Drum brake shoes have a large contact area, dissipate heat relatively slowly and commonly work under heavy-duty duty, so fibre selection leans toward reinforcement, heat resistance and length-to-diameter ratio. This article gives selection points and trial advice; Boer parameters are brochure data, governed by the batch outgoing report.

How drum shoes differ from disc pads: a drum shoe expands and rubs inside the brake drum, with a large contact area and a wide load distribution, but heat dissipates relatively slowly — heat builds up after continuous braking, and the duty is frequent in commercial vehicles and heavy-load scenarios. This duty values the fibre's reinforced toughness and high-temperature stability to prevent the shoe from cracking or losing blocks under repeated thermal–mechanical cycles.

Four selection points: reinforced toughness (prevent cracking and block loss under repeated stress — choose models with adequate L/D); heat-stable performance (slow heat dissipation, temperature rise after continuous braking — rely on the >1000°C melting-point common property); L/D orientation (longer fibres aid the interlocking network — BE-SL05 ≥60, BE-TL13/TL16 ≥80); shot control (hard particles affect uniformity and abrasion — industry generally <5%; Boer BE-SL05 and similar models <1%–<3%, subject to the batch report). L/D matters more on drums because under heavy-duty repeated expansion and contraction, a more continuous fibre network better holds the matrix and delays crack propagation — but too-long fibres can clump, so it is a balance of “adequate and dispersible”.

Trial advice for drum-shoe formulations: preselect a higher-L/D model for heavy duty and fix the other components; compare the dispersion uniformity and fracture section of two L/D grades; measure fade/recovery after continuous braking and wear rate; and observe for cracks after multiple thermal cycles, following the batch. Boer BE-series friction models can be candidate directions, but final drum-shoe fit must be validated by sampling and thermal-cycle testing under your own duty.

Key facts

• Applies to: drum brake shoes
• Duty: large contact area · slow cooling · heavy load
• Fibre orientation: reinforcement + heat resistance, L/D
• Boer references: BE-SL05 L/D≥60; BE-TL13/TL16 L/D≥80; shot <1–3%

The original article is in Chinese; see the Chinese version for the full text. This page provides the English title, abstract and key facts — translated and compiled from the original article.