Rotation Detection Device Guide Surface and Cover Structure

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Solution Overview

Problem

Existing rotation detection devices are prone to damage and displacement due to contact between the steering shaft and rotor caused by attachment or manufacturing errors, leading to potential damage and misalignment.

Innovation Solution

A rotation detection device featuring a wheel portion with a tubular structure and a projecting edge portion, where the steering shaft is guided through a cover portion to prevent direct contact with the rotor, and a chamfered ridge between the tubular and projecting edge portions reduces impact, along with a guide surface that decreases in diameter to facilitate smooth insertion and prevent interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the rotor is directly engaged with the shaft body without protective structures, then the device complexity is reduced, but the reliability deteriorates due to potential contact and damage from attachment or manufacturing errors

Engineering Contradiction:
Improvestructure complexityVSAvoidrotation detection reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces a protective cover structure that acts as an intermediary between the shaft body and the rotor. This cover includes a guide surface that guides the shaft body during insertion, preventing direct contact between the shaft body and the rotor's tubular portion, thereby avoiding damage while maintaining structural simplicity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies beforehand cushioning by designing the guide surface with a specific shape (decreasing diameter from top to bottom) that prevents the shaft body from contacting the rotor before potential misalignment occurs. This preventive design cushiones against potential damage from attachment or manufacturing errors

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Manufacturing precision

If the guide surface has a uniform diameter, then the manufacturing precision is improved, but the ease of operation deteriorates due to difficulty in smooth insertion of the shaft body

Engineering Contradiction:
Improveguide surface precisionVSAvoidshaft body insertion ease
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent applies spheroidality by designing the guide surface with a curved, tapered shape rather than a uniform cylindrical form. The guide surface's diameter decreases from top to bottom, creating a conical or frustoconical geometry that facilitates smooth insertion of the shaft body while remaining manufacturable

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Stability of the object's composition

If the projecting edge portion is positioned far from the rotational axis, then the rotor stability is improved, but the object-generated harmful factors increase due to higher risk of contact with the shaft body

Engineering Contradiction:
Improverotor stabilityVSAvoidcontact damage risk
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The protective cover structure serves as an intermediary that allows the projecting edge portion to maintain its stabilizing position far from the rotational axis while preventing it from contacting the shaft body. The guide surface and cover structure mediate between the shaft body and the projecting edge portion

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Prevents contact between the steering shaft and rotor even with errors, reducing damage and displacement, ensuring stable rotation and accurate detection.

Implementation Method 1

a magnet body rotating in response to rotation of the wheel portion so that a magnetic field of the magnet body changes

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentEP3640579B1Rotation detection device
Publication Date: 2022.12.28 ALPS ALPINE CO LTD
  • EP3640579B1 patent drawingFigure 1
  • EP3640579B1 patent drawingFigure 2
  • EP3640579B1 patent drawingFigure 3

AI summary

[Object] To provide a rotation detection device capable of preventing contact between a shaft body and a rotor even when the rotor has attachment errors or manufacturing errors, or capable of reducing damage to and displacements of components even when the contact occurs. [Solution] A wheel portion allows a shaft body that serves as a detection object to be inserted therein in a direction of a rotational axis from a position in front of the wheel portion, and is rotated about the rotational axis when the shaft body is rotated. The wheel portion includes a tubular portion in which the shaft body is inserted and a projecting edge portion extending away from the rotational axis at a front end of the tubular portion. The housing portion includes a cover portion having a hollow tubular opening portion in which the shaft body is inserted. The cover portion and the wheel portion are engaged with each other such that the opening portion is located on an inner side of the projecting edge portion.