Cain, P., "Performance Improvements in a Brake Wear Sensor Used in Off-Highway Vehicle Brake Safety Systems," SAE Technical Paper 2015-01-2728, 2015, doi:10.4271/2015-01-2728.
OEM benefit: Vehicle manufacturers desire continuous feedback in monitoring key safety related sub-assemblies. In this application, engineers are calculating the remaining brake pad life by continuously monitoring the current thickness of the brake pad friction material. This information is used in scheduling preventative maintenance activities and avoiding safety incidents. Unplanned machine down time and field repair expenses in earthmoving equipment are cost prohibitive. Today, this technology allows OEM's to have high confidence, continuous feedback on this critical vehicle safety feature, avoiding expensive, unplanned repairs and to improve field “up time” performance.Application challenge: to develop a reliable linear position sensor that is suitable for continuous monitoring of brake pad material thickness in a high pressure, high temperature, high vibration and contaminated environment typical of large construction (earthmoving) vehicles.This paper discusses the working principles of an appropriate inductive position sensing technology that has been released into volume production. Details will be provided that demonstrate a production proven device that can sense linear displacement through the wall of a pressure sealed stainless steel membrane, keeping the sensing electronics protected from the typical environmental contaminants that earthmoving machinery are frequently exposed to in normal usage.