Planetary Gear Sensor for Disc Brake Wear and Stroke Detection

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Solution Overview

Problem

Existing sensor devices for disc brakes face challenges in simultaneously achieving high resolution and large measuring range, leading to increased costs and complexity, particularly in detecting wear and actuation stroke with existing mechanical adjustment systems.

Innovation Solution

A sensor device with a planetary gear system that can switch between detecting wear and actuation stroke, using a single sensor gear to superimpose both input variables, allowing for high accuracy and adaptability with minimal parts, enabling efficient conversion for different applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single sensor is used to detect both wear and actuation stroke, then device complexity is reduced, but measurement precision deteriorates due to the conflicting requirements of large measuring range and high resolution

Engineering Contradiction:
Improvenumber of sensorsVSAvoidclearance detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The planetary gear system segments the measurement functions by directing different input movements to different gear components: wear detection through the sun gear and actuation stroke detection through the ring gear, allowing a single sensor to measure both parameters with high precision

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The planetary gear system enables the single sensor to perform multiple measurement functions simultaneously by superimposing wear and actuation stroke signals on the same sensor through different gear transmission paths

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

2Length of stationary object

If a sensor with large measuring range is used, then the measuring range is increased, but measurement precision deteriorates

Engineering Contradiction:
Improvemeasuring rangeVSAvoidclearance detection accuracy
Core Design Contradiction:
Length of stationary objectVSMeasurement precision

Solution Approach 1:

The planetary gear system divides the total measurement range into two segments: the sun gear handles the large wear path (60mm) while the ring gear handles the small actuation stroke (4.5mm), allowing each segment to be optimized for its specific range while maintaining high resolution

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a one-dimensional measurement approach to a two-dimensional gear system where radial and tangential movements are separated and transmitted through different gear components, enabling simultaneous large range and high precision measurement

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Measurement precision

If the actuation stroke is significantly smaller than the wear path, then the sensor must have both large measuring range and high resolution, but this leads to increased costs

Engineering Contradiction:
ImproveresolutionVSAvoidsensor requirements
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The planetary gear system segments the measurement tasks so that the sun gear transmits wear information and the ring gear transmits actuation stroke information to the same sensor, allowing the sensor to operate at optimal resolution for both parameters without requiring separate high-resolution sensors

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3071861B1Sensor device and disc brake comprising a sensor device
Publication Date: 2018.01.10 KNORR BREMSE SYSTEME FUER NUTZFAHIZEUGE GMBH
  • EP3071861B1 patent drawingFigure 1
  • EP3071861B1 patent drawingFigure 2
  • EP3071861B1 patent drawingFigure 3

AI summary

A sensor device (15) for a disc brake has a sensor gear mechanism (16) which can be coupled to at least one transmitter, wherein the sensor gear mechanism (16) is arranged in a housing as a planetary gear mechanism and has an input for a first variable, which can be detected by the sensor device (15) and which is associated with wear of the disc brake, and has an input for a second variable, which can be detected by the sensor device (15) and which is associated with an operating movement of the disc brake. The sensor device (15) can be changed over from a first state for detecting the first variable, which is associated with wear of the disc brake, and the second variable, which is associated with an operating movement of the disc brake, to a second state for detecting only the first variable, which is associated with wear of the disc brake.