Brake Apparatus Stroke Sensor External Mounting

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Solution Overview

Problem

The configuration of existing brake systems, particularly those using stroke sensors based on inductance or electromagnetic principles, faces challenges in accurately detecting piston displacement due to electromagnetic noise, which affects detection accuracy.

Innovation Solution

A brake apparatus with a master cylinder unit and a stroke sensor integrated together, where the stroke sensor is attached to the outer wall of the master cylinder unit, allowing for improved layout flexibility and noise reduction, enhancing detection accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the stroke sensor is mounted inside the master cylinder unit, then the detection accuracy is improved, but electromagnetic noise from the sensor affects the reliability of the detection system

Engineering Contradiction:
Improvedetection accuracyVSAvoiddetection reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The brake system is divided into separate functional units: the master cylinder unit containing electromagnetic components and the stroke sensor unit containing the detection sensor. This segmentation isolates the sensor from electromagnetic noise sources while maintaining detection accuracy through precise external positioning.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The master cylinder unit housing acts as an intermediary structure that provides a mounting surface for the stroke sensor. The sensor is positioned externally on the housing, using the housing as a mediator to achieve both accurate detection and electromagnetic isolation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the stroke sensor is mounted externally on the master cylinder unit, then electromagnetic noise interference is reduced, but the mountability and layout flexibility are improved

Engineering Contradiction:
Improvedetection reliabilityVSAvoidmountability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The stroke sensor and master cylinder unit are integrated into a single assembled component where the sensor is mounted on the external housing. This merging provides both electromagnetic isolation and simplified installation as a complete assembly unit.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The external mounting arrangement serves multiple functions: it provides electromagnetic shielding, enables flexible layout options during installation, and maintains detection accuracy. The housing serves both as a structural container and as a mounting surface for the sensor.

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

3Adaptability or versatility

If the stroke sensor is mounted externally on the master cylinder unit, then layout flexibility is increased, but the device complexity increases

Engineering Contradiction:
Improvelayout flexibilityVSAvoidassembly complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The stroke sensor is pre-mounted on the master cylinder unit housing during manufacturing, creating a pre-assembled module. This preliminary action simplifies final installation and reduces on-site assembly complexity while maintaining layout flexibility.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3072760B1Brake apparatus
Publication Date: 2020.02.19 HITACHI AUTOMOTIVE SYST LTD
  • EP3072760B1 patent drawingFigure 1
  • EP3072760B1 patent drawingFigure 2
  • EP3072760B1 patent drawingFigure 3

AI summary

An object of the present invention is to provide a brake apparatus capable of highly accurately detecting a stroke amount of a brake pedal. According to an aspect of the present invention, a brake apparatus includes a master cylinder unit and a stroke sensor. The master cylinder unit includes therein a piston configured to carry out a stroke via a rod axially actuated according to an operation performed by a driver on a brake pedal, and an oil passage through which brake fluid flows after flowing out according to the stroke of the piston. The stroke sensor is attached to an outer wall of the master cylinder unit and configured to detect an axial stroke amount of the piston.