Shifter Gear Splined Collar Offset Reduction

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Solution Overview

Problem

Conventional shifter gears experience significant thrust load and resulting friction due to a large offset between the gear part and spline centers, leading to instability and increased friction between the shift fork and shifter gear.

Innovation Solution

The shifter gear incorporates a splined collar that can rotate relative to the base part, reducing the offset between the gear and spline centers, and includes an oil passage for lubrication, while the splined collar acts as a supporting element to prevent axial direction falls and reduce friction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the shifter gear uses a conventional integrated spline design, then the structure is simple, but the offset between gear part center and spline center is large causing thrust load and friction

Engineering Contradiction:
Improvestructure simplicityVSAvoidthrust load and friction
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The spline is divided into two separate components: a splined collar and a base part. The splined collar is a separate component that can rotate relative to the base part, allowing the power transmission function to be separated from the supporting function. This segmentation enables the gear part center and spline center to be aligned, reducing thrust load and friction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The splined collar acts as an intermediary component between the gear part and the base part. It provides the spline engagement with the gear shift shaft while allowing relative rotation, thereby mediating the power transmission and supporting functions. This intermediary structure enables the offset reduction while maintaining functional integrity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the spline is configured with a rotatable splined collar, then the offset between centers is reduced and thrust load decreases, but the device complexity increases

Engineering Contradiction:
Improvethrust load and frictionVSAvoidstructure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The splined collar serves multiple functions: it provides spline engagement for power transmission, acts as a bearing surface for the gear part, and enables relative rotation to accommodate misalignment. By consolidating these functions into a single component, the overall structural complexity is minimized despite the functional requirements.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Object-affected harmful factors

If the splined collar is separated from the base part, then the offset is reduced and friction is restrained, but the number of parts increases

Engineering Contradiction:
Improvefriction between shifter gear and shift forkVSAvoidnumber of parts
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The splined collar is integrated with the gear part in such a way that they form a combined assembly that rotates together relative to the base part. This merging reduces the effective number of independent moving parts while still providing the benefits of the separated spline design for reducing friction and thrust load.

Inventive Principle:
Principle #5Merging (Combining)

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 significantly reduces thrust load and friction between the shifter gear and shift fork, enhancing stability and reducing the likelihood of axial direction falls by minimizing the offset and providing lubrication.

Implementation Method 1

Such thrust load causes a friction at the engaging part between the shift fork and the shifter gear. Furthermore, the thrust load also acts as a force attempting to bring the shifter gear down in the axial direction, further facilitating the friction.

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

The oil passage is configured to supply lubricating oil to the engaging part with the shift fork.

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP3002481B1Shifter gear
Publication Date: 2020.03.11 HONDA MOTOR CO LTD
  • EP3002481B1 patent drawingFigure 1
  • EP3002481B1 patent drawingFigure 2(a)~2(b)
  • EP3002481B1 patent drawingFigure 3(a)~3(b)

AI summary

To provide a shifter gear that reduces a thrust load occurred in a shifter gear and therefore can restrain a friction between the shifter gear and a shift fork. [Solution] A base part 11, a gear part 12, an engaging part 13 with a shift fork 30, and a spline 14 are included. The gear part 12 is disposed at an outer periphery of the base part 11. The engaging part 13 with the shift fork 30 is disposed at an outer periphery of the base part 11. The spline 14 is disposed at an inner periphery of the base part 11. The shifter gear 10 is mounted relatively slidable to a gear shift shaft 40 in an axis direction via the spline 14. The shifter gear 10 is mounted to be incapable of relative rotation around an axis. The shift fork 30 engaging the engaging part 13 is configured to perform a slide operation on the shifter gear 10. One part 14c of the spline 14 is configured with a splined collar 20 in an axis direction. The splined collar 20 is a different body from the base part 11. The splined collar 20 is able to relatively rotate to the part 11 around an axis.