Motorcycle Shift Spindle Recessed Portion for Sensor Detection

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Solution Overview

Problem

Existing speed change devices for motorcycles require high machining accuracy and complex assembly procedures, making them difficult to assemble and increasing costs, while also requiring precise attachment of separate rotary plates to the shift spindle, which complicates the assembly process and detection of rotation.

Innovation Solution

A speed change device with a shift spindle featuring a detection-target recessed portion on its cylindrical outer surface, allowing for accurate detection of rotation without the need for high machining accuracy, and a shift spindle sensor that can detect the rotation with high precision, enabling easy assembly and maintaining detection accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a separate rotary plate is attached to the shift shaft to detect rotation, then the detection accuracy of shift shaft rotation can be improved, but the assembly complexity increases and high machining accuracy is required

Engineering Contradiction:
Improvedetection accuracy of shift shaft rotationVSAvoidassembly complexity of shift shaft components
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The detection target is integrated directly into the shift shaft by forming a recessed portion on its outer circumferential surface, eliminating the need for a separate rotary plate. This merging of the detection target with the shift shaft itself simplifies the assembly structure while maintaining detection accuracy, as the recessed portion is formed as a single integrated feature rather than requiring attachment of additional components.

Inventive Principle:
Principle #5Merging (Combining)

2Measurement precision

If a separate rotary plate is attached to the shift shaft, then the detection accuracy can be improved, but the assembly procedure becomes fixed and difficult

Engineering Contradiction:
Improvedetection accuracyVSAvoidease of assembly
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

By integrating the detection target recessed portion directly into the shift shaft, the invention eliminates the need for separate attachment procedures. The recessed portion is formed as an integral feature of the shift shaft, allowing flexible assembly without fixed procedural constraints, thereby improving ease of manufacture while maintaining detection accuracy.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If the rotary plate is made long to increase detection accuracy, then the detection precision improves, but the structure becomes more prone to displacement and requires higher machining accuracy

Engineering Contradiction:
Improvedetection precisionVSAvoidmachining accuracy requirement
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

Instead of making the entire shift shaft or detection component longer, the invention creates a localized recessed portion on the outer circumferential surface of the shift shaft. This local modification provides sufficient detection reference points without requiring increased overall length or higher machining accuracy across the entire component, thereby improving detection precision while avoiding increased manufacturing complexity.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3196511B1Speed change device for motorcycle
Publication Date: 2018.07.25 HONDA MOTOR CO LTD
  • EP3196511B1 patent drawingFigure 1
  • EP3196511B1 patent drawingFigure 2
  • EP3196511B1 patent drawingFigure 3

AI summary

A speed change device for a motorcycle has a lost motion mechanism (73) associated with a shift rod (72) of a link mechanism (70) that transmits an operating force applied to a shift operating member (62) to a shift spindle (51). The speed change device is provided with a shift stroke sensor (75) that detects an amount of expansion/contraction stroke of the shift rod (72) and with a shift spindle sensor (55) that detects rotation of the shift spindle (51). Further provided is an output control device that controls the output of an internal combustion engine on the basis of detection signals of the shift stroke sensor (75) and the shift spindle sensor (55). The shift spindle (51) has a detection-target recessed portion formed by recessing a part of a cylindrical outer circumferential surface of the shift spindle (51). The shift spindle sensor (55) detects the rotation of the shift spindle (51) in cooperation with the detection-target recessed portion. Excellent assemblability of the shift spindle is thereby achieved without a high machining accuracy, together with an excellent accuracy of detection of the rotation of the shift spindle.