Brake Pad Thickness Measurement Using Hall Sensor
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Solution Overview
Problem
Existing methods for determining brake pad thickness in disc brakes, especially sliding caliper disc brakes, face challenges in withstanding vibrations and high temperatures, and are complex to retrofit, with existing sensors being prone to contamination and requiring cumbersome arrangements.
Innovation Solution
A magnetic field sensor based on the Hall principle, comprising a permanent magnet and a Hall sensor, is arranged in the longitudinal guide of the brake caliper, allowing for continuous electronic evaluation of brake pad wear, with an electronic evaluation unit connected to another sensor detecting the infeed path to calculate the wear of the inner brake lining using a subtraction method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ultrasonic transmitter and receiver are installed in a stationary manner on brake disc and pad carriers, then brake pad thickness can be measured, but the arrangement becomes complex and retrofitting existing brakes becomes difficult
Solution Approach 1:
The patent replaces complex ultrasonic mechanical sensor arrangements with a simple magnetic field sensor system. The magnetic field sensor detects changes in magnetic flux caused by brake pad wear, eliminating the need for complex ultrasonic transmitter-receiver assemblies and enabling easy retrofitting of existing brake systems.
Solution Approach 2:
The invention extracts the measurement function from complex mechanical sensor assemblies and isolates it into a simple magnetic field sensor integrated into the brake caliper. This separation allows the sensor to be easily installed on existing brakes without requiring complex mounting structures or disassembly of brake components.
2Measurement precision
If existing sensors are used in disc brakes, then brake pad wear can be detected, but the sensors are prone to contamination and cannot withstand vibrations and high temperatures
Solution Approach 1:
The patent employs a simple magnetic field sensor that is inherently robust and resistant to environmental factors. The sensor design accepts that components in the brake environment will experience wear and contamination, but the magnetic field measurement principle remains unaffected by these conditions, maintaining reliable operation throughout the sensor's service life.
Solution Approach 2:
The invention changes the measurement parameter from mechanical contact or acoustic signals (which are sensitive to contamination and vibration) to magnetic field detection. The magnetic field sensor measures changes in magnetic flux density caused by variations in brake pad thickness, a parameter that remains stable and measurable even under harsh vibrational and thermal conditions.
3Extent of automation
If a magnetic field sensor is arranged in the longitudinal guide of the brake caliper, then continuous electronic evaluation of brake pad wear is achieved, but the sensor must withstand harsh conditions including vibrations and high temperatures
Solution Approach 1:
The patent replaces mechanical wear indicators or contact-based sensors with a magnetic field sensor that operates electronically. The magnetic field measurement system provides continuous automated monitoring of brake pad thickness without mechanical contact, eliminating wear and contamination issues associated with mechanical systems while maintaining reliability under vibration and temperature extremes.
Solution Approach 2:
The magnetic field sensor system is designed to be self-sufficient in the harsh brake environment. The sensor integrates the permanent magnet and Hall sensor into a single unit that requires no external calibration, power conditioning, or protective housing beyond what is already present in the brake caliper structure. The system automatically compensates for environmental variations and provides continuous wear monitoring without intervention.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides robust and accurate continuous monitoring of brake pad wear, resistant to temperature and contamination, facilitating easy retrofitting and enabling precise electronic evaluation of brake pad thickness, ensuring reliable operation under harsh conditions.
Implementation Method 1
A magnetic field sensor based on the Hall principle, comprising a permanent magnet and a Hall sensor
Data Source
AI summary
The device has a brake caliper (4) arranged over a longitudinal guide (5) from a guide bore (7) and a guide spar (6) lengthwise-movable in relation to a brake carrier (2). Distance detecting units are arranged in a region of the longitudinal guide. The distance detecting units are in the form of magnetic field sensors (31). The guide bore is arranged in the brake caliper. The magnetic field sensor comprises a Hall sensor and a permanent magnet (32). The permanent magnet is placed at the guide spar. The Hall sensor is secured in a region of the guide bore.