Caliper Guide Sleeve Wear Sensing With Protected Hall Sensor

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Solution Overview

Problem

Existing disc brake guide assemblies face issues with free sliding due to manufacturing tolerances, thermal expansion, and deflection, and existing wear sensing arrangements are costly, prone to contamination, and restrict design flexibility.

Innovation Solution

A caliper guide assembly with a wear sensor mounted on a cap closing the bore, using a guide pin and bush with a non-circular inner profile and a Hall Effect sensor to detect brake pad wear, while minimizing contamination and accommodating thermal expansion and deflection through a void in the guide assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a wear sensor is integrated into the guide assembly, then wear status can be monitored accurately, but the device complexity increases

Engineering Contradiction:
Improvewear status detectionVSAvoidguide assembly structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The wear sensor is integrated directly into the guide pin or guide bushing, merging the sensing function with the existing guide structure. This eliminates the need for separate sensor mounting components and reduces overall device complexity while maintaining accurate wear detection capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The guide pin or guide bushing serves dual purposes: providing mechanical guidance for the caliper and housing the wear sensor. This multi-functionality reduces the number of separate components needed in the assembly.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If the sensor component extends into the guide bore, then wear can be detected, but the sensor is susceptible to environmental contamination and damage

Engineering Contradiction:
Improvewear detection capabilityVSAvoidenvironmental contamination
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

A protective seal or shield is introduced as an intermediary element between the sensor component and the external environment. This seal allows the sensor to detect wear through the guide bore while preventing direct exposure to contaminants, brake dust, and moisture.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

A flexible protective membrane or coating is applied over the sensor component, allowing mechanical wear detection while providing a barrier against environmental contamination. The flexible nature maintains sensor functionality while protecting against damage.

Inventive Principle:
Principle #30Flexible shells and thin films

3Ease of operation

If the guide assembly accommodates manufacturing tolerances and thermal expansion, then free sliding is achieved, but the design flexibility is restricted

Engineering Contradiction:
Improvefree sliding capabilityVSAvoiddesign flexibility
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The guide assembly incorporates dynamic clearance or adjustable positioning features that automatically adapt to thermal expansion and manufacturing tolerances. This allows the assembly to maintain free sliding capability without requiring overly restrictive design constraints.

Inventive Principle:
Principle #15Dynamics

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

Ensures smooth sliding of the caliper and provides accurate wear status indication to the vehicle operator, reducing maintenance costs and design constraints while protecting against contamination.

Implementation Method 1

using a guide pin and bush with a non-circular inner profile and a Hall Effect sensor to detect brake pad wear

Methodology Applied
Scientific EffectHall Effect: Hall Effect

Data Source

PatentEP3822505B1Brake continuous wear sensor (CWS) located in guide sleeve
Publication Date: 2023.01.04 MERITOR HEAVY VEHICLE BRAKING SYSTEMS (UK) LIMITED
  • EP3822505B1 patent drawingFigure 1
  • EP3822505B1 patent drawingFigure 2
  • EP3822505B1 patent drawingFigure 3

AI summary

A caliper guide assembly for a heavy vehicle disc brake. The caliper guide assembly comprises: a guide pin (11a) having a guide portion (15a); a guide bore (12a) having an opening and a guide surface arranged to receive the guide portion and permit relative axial sliding thereof; a wear sensor (62a) arranged to detect the position of the guide pin in relation to the guide bore, the wear sensor comprising a signal processing portion (68); and a cover (60a) arranged to close the opening of the guide bore. The signal processing portion is mounted to the cover.