Floating-Caliper Brake Wear Sensing for Uneven Pad Wear

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Solution Overview

Problem

Existing sliding caliper disc brake systems for motor vehicles face challenges in continuous wear sensing of brake linings without requiring replacement of wear sensors during pad changes and fail to accurately detect uneven wear between brake pads.

Innovation Solution

A sliding caliper disc brake system incorporating a rotary sensor with a shaft having a coarse thread that engages with a corresponding thread on an annular sensor component, allowing for displacement-based signal changes, and a wear sensor that determines the sum of brake lining and disc wear, with signals being added or compared in an evaluation circuit to provide a 'worst case' signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If wire loops are used in the friction material for wear detection, then wear limit detection is achieved, but the sensors require replacement when pads are changed

Engineering Contradiction:
Improvewear detection accuracyVSAvoidsensor replacement requirement
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The wear detection function is extracted from the consumable friction lining and transferred to the non-consumable caliper body. The sensor housing is integrated into the caliper body, making the sensor a permanent part of the braking system that does not require replacement with pad changes.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

A measuring element with a free end is introduced as an intermediary between the sensor housing and the friction lining. This measuring element can be optically, acoustically, or electrically evaluated and provides the actual wear measurement while being separate from both the sensor housing and the friction lining.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If only the wear limit of brake pads is detected, then simple wear sensing is achieved, but continuous wear detection is limited

Engineering Contradiction:
Improvesensor system simplicityVSAvoidcontinuous wear detection capability
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The sensor system is pre-configured with a measuring element that extends toward the friction lining before wear occurs. This allows continuous monitoring of the wear process from the beginning, rather than only detecting when a pre-set limit is reached.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The sensor system provides continuous feedback about the wear state through the evaluable measuring element. This enables real-time monitoring of friction lining thickness, allowing for proactive maintenance decisions based on actual wear rates rather than fixed replacement schedules.

Inventive Principle:
Principle #23Feedback

3Duration of action of moving object

If sliding caliper position is used to determine wear, then continuous monitoring is achieved, but uneven wear between pads cannot be detected

Engineering Contradiction:
Improvecontinuous monitoring capabilityVSAvoiduneven wear detection accuracy
Core Design Contradiction:
Duration of action of moving objectVSMeasurement precision

Solution Approach 1:

The wear detection is segmented into individual measurements for each brake pad. Each caliper assembly has its own sensor system that independently measures the wear of its associated friction lining, allowing comparison between left and right pads to detect uneven wear patterns.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The measuring element is positioned locally at each caliper assembly to measure wear at that specific location. This localized measurement approach allows detection of position-specific wear characteristics, enabling identification of uneven wear between different brake pads on the same axle.

Inventive Principle:
Principle #3Local quality

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

Enables continuous wear sensing without the need for wear sensor replacement and accurately accounts for uneven wear between brake pads, maximizing usable friction lining mass.

Implementation Method 1

a shaft having a coarse thread arranged on the lateral surface being provided between the first sensor component and the second sensor component, which engages with a corresponding coarse thread on the inside of the annular second sensor component, so that a displacement of the brake caliper of a rotation of the shaft by an angle α causes a change in the signal emitted by the wear sensor to the evaluation circuit

Methodology Applied
Scientific EffectScrew mechanism: Screw

Data Source

PatentEP2831447B2Floating-caliper disk brake of a motor vehicle
Publication Date: 2023.03.15 KNORR BREMSE SYSTEME FUER NUTZFAHIZEUGE GMBH
  • EP2831447B2 patent drawingFigure 1a~1b
  • EP2831447B2 patent drawingFigure 2
  • EP2831447B2 patent drawingFigure 3~4

AI summary

The invention relates to a disk brake of a motor vehicle, in particular of a utility vehicle, which disk brake has a brake caliper (3) that reaches over a brake disk (4) and that is supported on a guide bearing (8) in such a way that the brake caliper can be moved relative to a stationary brake carrier (2) and axially with respect to the brake disk (4), at least two brake linings (5, 6) having a lining carrier plate (52, 62) and a friction lining (51, 61) fastened thereto, wherein at least one brake lining (6) is arranged on the brake application side and at least one friction lining (5) is arranged on the back side of the brake disk (4), and a device for detecting brake lining wear, wherein the device for detecting the brake lining wear has a wear sensor that detects the travel (x) of the brake caliper, wherein a first sensor component is fastened to the brake caliper (3), which first sensor component is connected to a second sensor component lying on the guide bearing (8), wherein the wear sensor is connected to an evaluating circuit.