Brake Pad Wear and Temperature Sensing with Reconfigurable Circuits
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Solution Overview
Problem
Existing sensor assemblies for detecting the wear and temperature of braking members in vehicles are not sufficiently reliable, accurate, and are bulky, making them difficult to use on various braking devices, especially brake pads, due to the vulnerability of thermistors and their size.
Innovation Solution
A compact wear and temperature detecting unit is designed with a cascaded arrangement of independent electrical detection circuits on a flexible polyimide tape, using platinum RTDs for temperature detection and shearable wear detectors, which are connected to an electronic unit that reconfigures to maintain accuracy and reliability as the brake pad wears, allowing for precise temperature and wear monitoring without interfering with other circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thermistors are arranged in series on two branches to detect temperature and wear, then temperature and wear can be detected simultaneously, but the reliability decreases because breakdown of one thermistor causes entire assembly to fail
Solution Approach 1:
The sensor assembly is divided into multiple independent detection circuits, each with its own thermistor. These circuits are arranged in parallel rather than series, so that failure of one circuit does not affect the others. This segmentation maintains temperature detection accuracy while significantly improving reliability.
Solution Approach 2:
Each detection circuit is designed with local independence, having its own thermistor and signal processing path. This allows each circuit to maintain optimal local characteristics for temperature detection while the overall system gains redundancy and reliability through the distributed architecture.
2Measurement precision
If multiple thermistors are arranged in series to detect wear progression, then wear can be detected through voltage variation, but the device size increases making it difficult to use on brake pads
Solution Approach 1:
The detection of both temperature and wear is merged into a single integrated sensor assembly that uses the same thermistor array for both functions. The thermistors serve dual purposes: temperature sensing and wear progression detection through their progressive elimination, eliminating the need for separate detection mechanisms and reducing overall size.
Solution Approach 2:
The thermistor array is designed to perform multiple functions simultaneously: temperature detection, wear detection through voltage variation, and wear detection through progressive elimination. This multi-functionality allows a compact single assembly to replace what would otherwise require multiple separate sensors.
3Measurement precision
If thermistors are positioned relative to mobile braking member to detect temperature behavior, then temperature detection is possible, but the accuracy decreases due to varying relative positions during braking
Solution Approach 1:
The sensor assembly is designed with flexible mounting and flexible circuit board that can accommodate the dynamic movement and deformation that occurs during braking. The thermistors are positioned and connected in a way that maintains electrical connectivity and measurement accuracy despite the changing mechanical conditions during brake operation.
4Ease of operation
If a compact sensor assembly is designed for use on brake pads, then ease of installation improves, but the reliability and accuracy may decrease due to space constraints
Solution Approach 1:
The sensor assembly is designed with a compact nested structure where the attachment body houses the electronic unit, which in turn contains the detection circuits and thermistor array. This nested arrangement achieves maximum compactness while maintaining all necessary functional components, allowing easy installation on brake pads without sacrificing reliability or accuracy.
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 a reliable, precise, and compact unit that accurately monitors wear and temperature with minimal deviation (typically 3-5 degrees) and is adaptable to various braking systems, ensuring efficient operation and reduced construction costs.
Implementation Method 1
using platinum RTDs for temperature detection
Implementation Method 2
shearable wear detectors, which are connected to an electronic unit that reconfigures to maintain accuracy and reliability as the brake pad wears
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A braking member of a vehicle is joined to a unit (7) for detecting wear and temperature of the braking member; the unit (7) comprising a sensing assembly (8), an electrical connector adapted to enable connection of the unit (7) to an electrical circuit of the vehicle, and an electrical wiring (11) for connection of the sensing assembly (8) to the electrical connector; the sensing assembly (8) comprising an attachment body having an axis and configured to be stably connected to the braking member; the attachment body housing wear detection means (36) and temperature sensor means (35) arranged along the axis and embedded in the attachment body, while the electrical connector houses an electronic unit for receiving and processing signals and for sending an output signal through the electrical connector.