Shift Drum Control With Learned Angle Correction and Fewer Parts

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Solution Overview

Problem

Existing transmission apparatuses with dual-clutch transmissions and variable speed drive mechanisms have a complex structure and high component count, necessitating multiple sensors and mechanisms to accurately control the rotation of the shift drum, which increases cost and complexity.

Innovation Solution

A transmission apparatus with a simplified structure that integrates a shift drive gear with a shift spindle, a drum center, and a stopper mechanism, using a spindle angle sensor to detect the shift spindle's rotation, and a shift control device to learn and correct the control value based on the difference angle between detected spindle and drum angles, eliminating the need for additional angle sensors and mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a pole ratchet mechanism and speed increasing mechanism are added to accurately detect the rotation angle of the shift drum, then the measurement precision of the shift drum angle is improved, but the device complexity and component count increase

Engineering Contradiction:
Improveshift drum angle detection precisionVSAvoidvariable speed drive mechanism complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the complex pole ratchet mechanism and speed increasing mechanism from the variable speed drive mechanism. Instead of using these additional mechanisms to achieve accurate angle detection, the invention directly uses a single angle sensor to detect the shift drum rotation angle, thereby maintaining measurement precision while significantly reducing device complexity and component count

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the angle detection function directly into the shift drum assembly by integrating a single angle sensor that detects both the shift drum position and the shift driven gear position. This consolidation eliminates the need for separate detection mechanisms and reduces the overall system complexity while maintaining accurate control capability

Inventive Principle:
Principle #5Merging (Combining)

2Manufacturing precision

If multiple angle sensors and a speed increasing mechanism are provided to accurately control shift drum rotation, then the control precision is improved, but the manufacturing cost increases

Engineering Contradiction:
Improveshift drum position control precisionVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent replaces expensive, complex mechanical mechanisms (pole ratchet mechanism, speed increasing mechanism, multiple sensors) with a simpler, more cost-effective single angle sensor solution. This substitution maintains the required control precision while significantly reducing manufacturing costs by eliminating unnecessary components

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Adaptability or versatility

If the number of gear positions of the shift drum is increased to provide more shift stages, then the adaptability of the transmission is improved, but the intervals between gear positions become narrower and control difficulty increases

Engineering Contradiction:
Improvetransmission gear ratio rangeVSAvoidshift drum rotation angle detection difficulty
Core Design Contradiction:
Adaptability or versatilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent replaces complex mechanical detection mechanisms with electronic angle sensor technology. The single angle sensor can accurately detect the shift drum rotation angle even when gear position intervals are narrow, providing precise digital feedback that is easier to process and control than mechanical detection methods, thereby maintaining high adaptability while reducing detection difficulty

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP4386235B1Speed-changing device
Publication Date: 2025.12.31 HONDA MOTOR CO LTD
  • EP4386235B1 patent drawingFigure 1
  • EP4386235B1 patent drawingFigure 2
  • EP4386235B1 patent drawingFigure 3

AI summary

A control value is corrected and learned based on a difference angle Δϕ between a drum shaft conversion spindle integration angle ϕs obtained by converting a detected spindle angle detected by a spindle angle sensor 78 into a drum angle and a detected drum angle ϕd detected by a drum angle sensor 89, over a predetermined learning time T from when the shift motor 61 is driven, and a drive engagement portion 83d of a shift driven gear 83 reduces the play angle to abut on a driven engagement portion 82d of a drum center 82 to accompany the driven engagement portion 82d. In this manner, rotation of a shift drum 80 can be accurately controlled by the shift motor 61, while the number of components of a variable speed drive mechanism 60 is reduced.