Parallel Axis Transmission Layout Flexibility via Starting Clutch

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Solution Overview

Problem

Conventional parallel axis type transmissions face limitations in layout planning due to the fixed arrangement of shifting clutches, leading to poor choices in design and potential power disruption during shifting.

Innovation Solution

A parallel axis type transmission with a starting clutch connecting the input shaft to both power transmitting paths, employing a synchro-mesh type mechanism and dog clutch gears without synchronizer rings, allowing for flexible layout options and smooth power transmission during shifting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If shifting clutches are arranged at fixed positions in conventional transmissions, then the structure is simple, but the layout plan choices are limited

Engineering Contradiction:
Improvelayout plan choicesVSAvoidclutch arrangement structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The starting clutch is designed to serve multiple functions: it controls power transmission to both the first and second power transmitting paths, and enables flexible layout configurations. By making the clutch arrangement universal rather than dedicated to a single path, the transmission achieves greater layout versatility without proportionally increasing complexity.

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

Solution Approach 2:

The transmission is segmented into two independent power transmitting paths (first and second paths), each with its own shifting clutch and gear sets. This segmentation allows each path to be independently configured and positioned, enabling diverse layout plans while maintaining structural simplicity within each segment.

Inventive Principle:
Principle #1Segmentation

2Speed

If synchro-mesh mechanism is used for path shifting, then shifting is smooth and rapid, but the mechanism has small inertia which may cause power transmission interruption

Engineering Contradiction:
Improveshifting speedVSAvoidpower transmission continuity
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The starting clutch is engaged in advance before path shifting occurs, preparing the power transmission path. This preliminary engagement ensures that when the synchro-mesh mechanism quickly shifts paths, the power transmission is already prepared and can continue without interruption, despite the small inertia of the shifting mechanism.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The dual clutch configuration with the starting clutch ensures continuous power transmission during path shifting. While one clutch is shifting paths, the other maintains power flow, and the starting clutch provides backup engagement to ensure uninterrupted power delivery throughout the shifting process.

Inventive Principle:
Principle #20Continuity of useful action

3Ease of manufacture

If dog clutch gears without synchronizer rings are used, then manufacturing cost is reduced, but gear shifting may be less smooth

Engineering Contradiction:
Improvemanufacturing costVSAvoidshifting smoothness
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The synchronizer rings are extracted (removed) from the dog clutch gear assembly. By taking out the synchronizer rings, the manufacturing process is simplified and costs are reduced. The remaining dog clutch gears with conical surfaces provide sufficient friction for engagement without the added complexity and cost of synchronizer rings.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent accepts a certain level of wear and potential replacement for the dog clutch gears without synchronizer rings. By using simpler, cheaper dog clutch gears that may have shorter service life compared to synchronizer-equipped gears, the overall manufacturing cost is significantly reduced while maintaining acceptable operational performance.

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

Data Source

PatentEP3249263B1Parallel axis type transmission
Publication Date: 2019.11.06 KYOWA METAL WORKS
  • EP3249263B1 patent drawingFigure 1
  • EP3249263B1 patent drawingFigure 2
  • EP3249263B1 patent drawingFigure 3

AI summary

A transmission (10) includes a first power transmitting path (10a) of gears that obtains odd number speeds and has an output part, a second power transmitting path (10b) of gears that obtains even number speeds and has an output part; a first gear shifting part (24) incorporated in the first power transmitting path to obtain one of the odd number speeds, a second gear shifting part (25) incorporated in the second power transmitting path to obtain one of the even number speeds, and a path shifting part (16) that is arranged between the first and second power transmitting parts. The path shifting part shifts the first or second power transmitting path to output power to the output shaft (27).