Brake Caliper Deformation Measurement via Magnetic Sensor
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Solution Overview
Problem
Existing methods for measuring deformation of brake calipers to determine clamping force in disc brakes are not sufficiently accurate or protected from external influences like water and dirt, and are affected by temperature changes.
Innovation Solution
A holder immovably connected to the brake caliper at a fastening point, with a measurement location at a distance from the attachment point, allowing for relative movement that is measured using a magnetic sensor or strain gauge, integrated within the caliper to protect from external influences and minimize temperature effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a strain gauge is attached to the yoke of the brake caliper to measure deformation, then the clamping force can be measured, but the measurement is affected by temperature changes and external influences like water and dirt
Solution Approach 1:
The patent introduces a magnetic field as an intermediary for force measurement. A permanent magnet is attached to the movable component, and a magnetic sensor (AMR or GMR type) measures changes in the magnetic field caused by clamping force. This magnetic field intermediary protects the measurement system from direct exposure to water, dirt, and temperature extremes while maintaining measurement accuracy.
Solution Approach 2:
The patent replaces traditional mechanical strain gauges with a magnetic sensing system. Instead of using electrical strain gauges that are susceptible to environmental factors, the system uses magnetic field sensing where a permanent magnet interacts with a magnetic sensor through a non-magnetic barrier, eliminating direct mechanical and environmental contact.
2Object-affected harmful factors
If a magnetic sensor is arranged between the friction brake lining and the brake caliper to measure clamping force, then the measurement is protected from external influences, but the device complexity increases
Solution Approach 1:
The magnetic sensor system serves multiple functions: it measures clamping force, operates protected from environmental factors, and can be integrated into existing brake caliper designs without requiring separate measurement systems for different conditions.
Solution Approach 2:
The patent utilizes changes in magnetic field parameters (strength, direction) in response to mechanical displacement caused by clamping force. The AMR or GMR sensor detects these magnetic parameter changes, providing a simplified measurement approach compared to complex mechanical measurement systems.
3Measurement precision
If the measurement location is placed at a distance from the attachment point of the holder, then measurement accuracy increases due to larger relative movement, but the holder must be designed to minimize its own deformation
Solution Approach 1:
The patent applies different material properties to different parts of the measurement system. The holder is made from a material with low thermal expansion and high rigidity to minimize its own deformation, while the magnetic sensor is positioned at a location that maximizes sensitivity to caliper deformation. This local differentiation of material and functional properties resolves the contradiction between measurement sensitivity and measurement reliability.
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
This solution provides high measurement accuracy and protection from external factors, allowing for precise regulation of braking force without being affected by clamping force or temperature changes, enhancing the reliability of disc brake performance.
Implementation Method 1
A change in a gap width at a free end of the L-shaped element is measured in order to measure a deformation of the brake caliper as a result of a clamping force when the brake is actuated
Implementation Method 2
The published application DE 103 14 449 A1 instead proposes the arrangement of a magnetic sensor between a friction brake lining and the brake caliper, which measures changes in a magnetic field, for example of a permanent magnet, due to the clamping force. The published application mentioned proposes AMR or GMR sensors, which are known as such, as magnetic sensors.
Implementation Method 3
DE 103 28 242 A1 discloses attaching a strain gauge in the area of the yoke of a brake caliper in order to measure the deformation of the brake caliper
Implementation Method 4
DE 102 01 555 A1 proposes arranging a piezo element between a friction brake lining and the brake caliper, with which the pressing force of the friction brake lining on the brake disc and thus the clamping force of the disc brake itself is measured
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a brake caliper (1) of an electromechanical disk brake (2). According to the invention, in order to measure a widening of a brake caliper (1) when the brake is activated, a rod-shaped support (13) which is clamped on one side, is arranged in a cavity (12) in a yoke (3) of the brake caliper (1), perpendicular to a brake disk (6) and a movement of the free end of the support (13) is measured, for example by means of a magnetic sensor (14). The widening of the brake caliper (1) is a measurement for the clamping force when the brake disk is actuated.