Floating Caliper Brake Clearance Determination

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Solution Overview

Problem

Existing methods for determining brake clearance in sliding-caliper disc brakes are prone to inaccuracies due to reliance on mathematical interpolation, which can lead to unreliable and inaccurate results.

Innovation Solution

A method involving the detection of displacement and pressure signals using sensors, with averaging of multiple data points to calculate a mean value, and a negative clearance determination based on a difference value exceeding a predetermined limit, allowing for continuous electronic evaluation and improved reproducibility and accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If mathematical interpolation methods are used to determine brake clearance from position values, then the determination can be performed continuously during driving, but the results become inaccurate and unreliable

Engineering Contradiction:
Improvecontinuous determination capabilityVSAvoidclearance determination accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent uses feedback by continuously monitoring the relationship between brake pressure and caliper position during driving, comparing actual measurements against expected values to detect negative clearance conditions. The control unit processes real-time sensor data and provides feedback warnings when clearance becomes negative, enabling continuous accurate monitoring without relying on inaccurate interpolation methods.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If multiple displacement signals are averaged to determine mean position, then measurement uncertainties and variance are reduced, but the processing complexity increases

Engineering Contradiction:
Improveposition measurement accuracyVSAvoiddata processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges multiple displacement signals from the displacement sensor into a single mean position value through averaging. This combining of multiple measurements reduces the impact of individual measurement uncertainties and variance, providing a more reliable mean position for clearance determination while the control unit handles the processing efficiently.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If brake clearance is monitored using ultrasonic methods with transmitters and receivers, then wear detection capability is improved, but the device complexity and cost increase

Engineering Contradiction:
Improvewear detection reliabilityVSAvoidsensor system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes the displacement sensor serve multiple functions: it measures both the position of the brake caliper for clearance determination and indirectly monitors brake pad wear through the relationship between pressure and position. This multi-functionality eliminates the need for separate ultrasonic transmitters and receivers, reducing device complexity while maintaining reliable wear detection capability through the existing sensor system.

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

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 method significantly increases the reliability and accuracy of brake clearance determination by averaging multiple data points, reducing variance and measurement uncertainties, and providing real-time feedback to the driver through digital displays or warning signals.

Implementation Method 1

the displacement of the brake caliper relative to the brake carrier is detected as a displacement signal by a displacement sensor

Methodology Applied
Scientific EffectDisplacement sensing:

Implementation Method 2

the brake actuation pressure is detected by a pressure sensor as a pressure signal

Methodology Applied
Scientific EffectPressure sensing:

Data Source

PatentEP3385137B1Method for determining the play of a floating calliper disc brake
Publication Date: 2019.05.15 BPW BERGISCHE ACHSEN KG
  • EP3385137B1 patent drawingFigure 1
  • EP3385137B1 patent drawingFigure 2

AI summary

The invention relates to a method for controlling the brake clearance of a sliding caliper disc brake, which comprises a chassis-mounted brake carrier, a brake disc, and a brake caliper that overlaps the brake disc and brake pads on both sides of the brake disc, wherein: - the displacement of the brake caliper relative to the brake carrier is detected as a displacement signal by means of a displacement sensor, - the brake actuation pressure is detected by a pressure sensor, - times and/or time intervals are detected. The method comprises the following steps: a) with the clamping device not activated and also not activated for a preceding time interval Δt, detection of a plurality of displacement signals S1, S2, ...and calculating an average value SM of the position signals thus recorded, b) after activation of the clamping device, recording a pressure p1 at time t1, when both brake pads first make contact with the brake disc, and a pressure p2 at time t2, when the clamping device has built up brake pressure, c) recording a plurality of position signals W1, W2, ... within the time interval t1 to t2 and calculating an average value SA of the position signals thus recorded, d) calculating the difference value SA - SM, e) making a negative clearance determination in the control unit, provided that the calculated difference value SA - SM exceeds a predetermined limit value.