Segmented Metal Shaft Stroke Sensor for Thermal Stability

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Solution Overview

Problem

Existing stroke sensors face challenges in maintaining high detection accuracy due to size accuracy issues with plastic holders and thermal deformation, especially in applications with significant temperature changes, leading to axial displacement and reduced performance.

Innovation Solution

A stroke sensor design featuring a shaft composed of multiple metal shaft members connected along an axial line, with slide parts that regulate movement and prevent thermal deformation, allowing for improved size accuracy and detection precision without the need for complex molding processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the holder is made of plastic and components are integrally molded, then manufacturing complexity is reduced, but size accuracy deteriorates due to molding errors and thermal deformation

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidsize accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The shaft is divided into multiple shaft members (first shaft member and second shaft member) connected together, allowing each component to be manufactured separately with high precision metal machining rather than complex plastic molding, thereby improving size accuracy while maintaining manufacturing feasibility

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses metal materials for the shaft members instead of plastic, combining the advantages of metal (high size accuracy, thermal stability) with a structured design that avoids the need for complex integrally molded plastic components

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If multiple plastic components are assembled, then device flexibility is improved, but detection accuracy deteriorates due to accumulation of size errors and axial displacement

Engineering Contradiction:
Improvecomponent assembly flexibilityVSAvoiddetection accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The shaft is segmented into multiple metal shaft members connected by connection parts, maintaining assembly flexibility while using metal material to eliminate accumulation of size errors that occurs with plastic components

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the material parameter from plastic to metal for the shaft members, which fundamentally alters the dimensional stability and eliminates the accumulation of size errors while preserving the segmented structure's assembly flexibility

Inventive Principle:
Principle #35Parameter changes

3Weight of moving object

If the holder is made of plastic, then weight is reduced, but detection accuracy deteriorates due to thermal deformation in high temperature environments

Engineering Contradiction:
Improveshaft weightVSAvoiddetection accuracy
Core Design Contradiction:
Weight of moving objectVSMeasurement precision

Solution Approach 1:

The invention uses metal material for the shaft members to replace plastic, eliminating thermal deformation issues in high temperature environments while maintaining a lightweight design through the segmented structure and appropriate metal selection

Inventive Principle:
Principle #40Composite materials

4Device complexity

If integrally molded plastic components are used, then device complexity is reduced, but attachment complexity increases due to required molding processes

Engineering Contradiction:
Improvestructural complexityVSAvoidattachment process complexity
Core Design Contradiction:
Device complexityVSEase of manufacture

Solution Approach 1:

The shaft is divided into separate metal shaft members that can be manufactured using standard metal machining processes and assembled through simple connection parts, avoiding complex molding processes while maintaining structural simplicity

Inventive Principle:
Principle #1Segmentation

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 solution enhances size accuracy, prevents axial displacement, and maintains high detection accuracy across varying temperatures, while simplifying the attachment process between shaft and detected body.

Implementation Method 1

a magnetic detection element that detects the magnetic field of the magnet

Methodology Applied
Scientific EffectMagnetic field detection: Magnetic Field

Implementation Method 2

a slide part that is in contact with an inner wall of the housing and that slides so as to regulate a movement of the shaft in a direction that is crossed with the axial line

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3264028B1Stroke sensor and saddle riding type vehicle
Publication Date: 2020.04.29 NIPPON SEIKI CO LTD
  • EP3264028B1 patent drawingFigure 1
  • EP3264028B1 patent drawingFigure 2
  • EP3264028B1 patent drawingFigure 3

AI summary

A stroke sensor (35) includes: a shaft (40) that extends in an axial line direction; a detected body (71) that is fixed to the shaft (40); a housing (50) that extends along the shaft (40), that houses the shaft (40), and that supports the shaft (40) slidably in the axial line direction; and a detection body (72) that detects a movement amount of the detected body (71) which moves in accordance with sliding of the shaft (40), wherein the shaft (40) includes a plurality of shaft members (41, 42) that are connected to each other in the axial line direction and that are formed of metal, and a slide part (45, 47) that is in contact with an inner wall of the housing (50) and that slides so as to regulate a movement of the shaft (40) in a direction that is crossed with the axial line (C1) is provided on each of the plurality of shaft members (41, 42).