Sensor Arrangement Structure with Radial Ribs for Foreign Material Discharge

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Solution Overview

Problem

Existing sensor arrangements in sprocket covers are ineffective in preventing the intrusion of foreign materials and fail to effectively discharge them, leading to potential malfunctions due to the high-speed environment within the sprocket cover.

Innovation Solution

A sensor arrangement structure featuring a disc portion with radial ribs and cover-side ribs that guide foreign materials outward by centrifugal force, with the detector positioned inward to prevent intrusion and ensure effective discharge, and strategically sized gaps to prevent jamming.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the sensor is disposed within the sprocket cover to prevent foreign material intrusion, then the sensor is protected from foreign material, but foreign material can still intrude between the disc portion and the inner surface portion of the output shaft cover

Engineering Contradiction:

Improvesensor protection from foreign materialVSAvoidforeign material intrusion between disc portion and inner surface portion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The disc portion is segmented with multiple ribs extending radially outward, creating multiple barriers and guidance paths that segment the space between the disc portion and the inner surface portion of the output shaft cover. This segmentation prevents foreign material from moving freely and guides it outward toward the detector area where it can be effectively removed.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The ribs on the disc portion act as intermediary structures that mediate between the rotating disc portion and the stationary inner surface portion of the output shaft cover. These ribs create a dynamic barrier that, combined with the centrifugal force, effectively prevents foreign material from reaching the sensor area while allowing the rotation to continue uninterrupted.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If the detector is disposed close to the disc portion to detect rotational speed, then the detection accuracy is improved, but the detector becomes more vulnerable to foreign material intrusion

Engineering Contradiction:

Improverotational speed detection accuracyVSAvoiddetector vulnerability to foreign material

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The solution moves the detection function to a different dimensional space by using magnetic coupling through the disc portion. The detector is positioned in a safe area while still being able to detect rotational speed through the magnetic field generated by the rotating disc portion, thus achieving both close detection and foreign material protection.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The mechanical contact-based detection system is replaced with a magnetic field-based detection system. The detector no longer needs to be in direct proximity to the disc portion to detect rotational speed, as the magnetic field can penetrate through the disc portion, allowing the detector to be positioned in a protected area while maintaining detection accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If the ribs are formed to extend radially outward to guide foreign material, then foreign material discharge is improved, but the structural complexity of the disc portion increases

Engineering Contradiction:

Improveforeign material discharge efficiencyVSAvoiddisc portion structural complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

Instead of making the entire disc portion complex, the ribs are added only as needed in specific locations on the disc portion surface. This local modification approach allows foreign material guidance functionality to be added with minimal impact on the overall structural complexity of the disc portion.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Rather than trying to contain foreign material within the sprocket cover, the design inverts the approach by actively guiding foreign material outward toward the detector area using the ribs and centrifugal force, where it can be naturally discharged. This inversion simplifies the overall system by eliminating the need for complex sealing and removal mechanisms.

Inventive Principle:

Principle #13The other way round (Inversion)

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 configuration reliably prevents foreign material intrusion and ensures effective discharge, maintaining sensor performance by converting rotational force into radial force for efficient foreign material removal and minimizing the risk of jamming.

Implementation Method 1

the foreign material is guided toward the outside in the radial direction of the disc portion through the ribs by the centrifugal force of the rotating disc portion

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentUS9651438B2Sensor arrangement structure

Publication Date: 2017.05.16 HONDA MOTOR CO LTD

AI summary

A sensor arrangement structure includes an output shaft provided with a disc portion at a leading end portion thereof. An output shaft cover has an inner surface portion disposed along and close to the disc portion. The disc portion is provided with ribs, the ribs extending in a radial direction of the disc portion while protruding toward the inner surface portion. A detector is disposed more inward in the radial direction of the disc portion than the ribs.