Disc Brake Pad Wear Detection Using Clamping Stroke Length

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Solution Overview

Problem

Existing brake pad wear sensors only detect advanced wear and do not identify intermediate wear levels, increasing the risk of accidents and requiring additional cost during manufacturing.

Innovation Solution

A method to determine brake pad lining wear by measuring the stroke length of the clamping element from a reference position to a contact position, using existing sensors to detect early and intermediate wear conditions without additional sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a pad wear detector is used to detect brake lining wear, then wear detection capability is improved, but manufacturing cost increases significantly

Engineering Contradiction:
Improvewear detection capabilityVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The brake system uses its own existing components (electric motor, position sensor) to perform wear detection automatically. The control unit calculates wear by monitoring the motor's stroke length and position data, eliminating the need for external wear detectors and reducing manufacturing costs while maintaining detection capability

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The electric motor and position sensor serve dual purposes: controlling brake activation and simultaneously monitoring wear conditions. This multi-functionality allows the system to detect wear without adding dedicated detection hardware, resolving the contradiction between detection capability and manufacturing cost

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

2Measurement precision

If a pad wear detector is used to detect brake lining wear, then wear detection capability is improved, but device complexity increases

Engineering Contradiction:
Improvewear detection capabilityVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The existing electric motor and position sensor perform both brake control and wear monitoring functions. The control unit processes position data to calculate wear, eliminating the need for separate wear detector components and reducing overall device complexity

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

Solution Approach 2:

The wear detection function is merged with the existing brake control system. The control unit integrates position sensor data with motor control operations, combining multiple functions into a single system rather than adding separate detection hardware

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If traditional wear detection methods are used, then manufacturing cost is reduced, but wear detection is delayed until advanced wear occurs

Engineering Contradiction:
Improvemanufacturing costVSAvoidwear detection timing
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The system continuously monitors the position sensor data during normal brake operation to track cumulative stroke length. This continuous monitoring enables early wear detection throughout the brake lining's life rather than waiting for advanced wear, maintaining reliability without increasing manufacturing cost

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The control unit continuously receives position feedback from the sensor and calculates wear in real-time based on cumulative stroke length. This feedback mechanism enables continuous wear assessment during normal operation, providing early detection while using only existing system components

Inventive Principle:
Principle #23Feedback

4Measurement precision

If the clamping member stroke length is measured to determine wear, then wear detection accuracy is improved, but energy consumption increases

Engineering Contradiction:
Improvewear detection accuracyVSAvoidenergy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system uses position sensor data that is continuously generated during normal brake operation to calculate wear. No additional measurement actions are required, and the wear calculation uses existing operational data, avoiding additional energy consumption while maintaining detection accuracy

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The brake system uses its own operational data (motor position and stroke length) to perform self-diagnosis for wear detection. This self-service approach extracts wear information from existing operational parameters without requiring separate high-energy measurement processes

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4375151B1Method for determining a wear state of a brake lining of a brake pad of a disc brake for a vehicle
Publication Date: 2026.04.22 ASTEMO FRANCE
  • EP4375151B1 patent drawingFigure 1~2
  • EP4375151B1 patent drawingFigure 3A~4

AI summary

The invention relates to a method for determining the wear condition of a brake pad lining in a disc brake. The disc brake comprises an electric motor, a clamping element, a disc, and a brake pad. According to this method: a) a stroke length (d1, d2, d3) of the clamping element is determined from a reference position (14), away from the brake pad, to a contact position (15, 15'), corresponding to the position of the clamping element when it comes into contact with the brake pad, and b) a wear condition of the lining is deduced by determining the difference (d4) between the stroke length of the clamping element and a reference length.