Shifting Fork Transmission Layout Without a Neutral Position

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Solution Overview

Problem

Existing vehicle transmission systems with electrical motors face space limitations and complexity due to the need for multiple actuators to manage different gear states, often requiring inefficient movements of the sleeve to engage and disengage dog clutches.

Innovation Solution

A transmission design utilizing a shifting fork that moves in one direction to engage and disengage dog clutches, eliminating the need for a centered neutral position and allowing for a more compact design with reduced shifting times by arranging predetermined positions sequentially without intermediate selectable gear states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional sleeve movement system is used to engage dog clutches from a centered neutral position, then the transmission can achieve multiple gear states, but the transmission size and actuator complexity increase

Engineering Contradiction:

Improvegear state selection capabilityVSAvoidactuator system complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent removes the centered neutral position from the transmission system, extracting the unnecessary intermediate state. The shifting fork moves directly between first and second predetermined positions without returning to center, eliminating the need for complex multi-position actuation while maintaining gear state selection capability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of moving the sleeve from a centered neutral position to engage dog clutches (conventional approach), the patent inverts the approach by having the shifting fork move directly between two predetermined positions in one direction only, engaging dog clutches along the path without requiring a neutral starting point

Inventive Principle:

Principle #13The other way round (Inversion)

2Adaptability or versatility

If the sleeve moves from centered neutral position to engage dog clutches, then gear states can be achieved, but the shifting time increases due to back-and-forth movement

Engineering Contradiction:

Improvegear state achievementVSAvoidshifting time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The dog clutches are pre-positioned along the axial path between the first and second predetermined positions. The shifting fork engages them sequentially during its one-directional movement, eliminating the need for back-and-forth motion and reducing shifting time while maintaining gear state achievement

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The shifting fork performs continuous useful action by moving in one direction from the first predetermined position to the second, engaging dog clutches along the way. This eliminates idle back-and-forth movement, maintaining continuous productive motion during gear shifts

Inventive Principle:

Principle #20Continuity of useful action

3Adaptability or versatility

If multiple actuators are used to manage different gear states, then comprehensive gear control is achieved, but the transmission size increases due to space limitations

Engineering Contradiction:

Improvegear state controlVSAvoidtransmission size

Core Design Contradiction:

Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The shifting fork serves multiple functions: it moves axially between predetermined positions, engages and disengages dog clutches, and selects gear states all in one component. This multi-functionality eliminates the need for multiple separate actuators, reducing transmission size while maintaining comprehensive gear state control

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the functions of multiple actuators into a single shifting fork mechanism. The fork combines axial movement capability with dog clutch engagement functionality, consolidating what would traditionally require separate actuators into one integrated component, thereby reducing overall transmission size

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS12163586B2Transmission

Publication Date: 2024.12.10 NINGBO GEELY AUTOMOBILE RES & DEV CO LTD

AI summary

A transmission includes a shifting fork. The transmission has a first gear state and a second gear state being selectable by means of the shifting fork. The shifting fork is displaceable in an axial direction between a first predetermined position and a second predetermined position. The first gear state is provided when the shifting fork is placed in the first predetermined position and the second gear state is provided when the shifting fork is placed in the second predetermined position. The first predetermined position and the second predetermined position are arranged one after the other without any further predetermined position providing a further selectable gear state arranged between the first predetermined position and the second predetermined position. The first gear state provides a first gear of the transmission and the second gear state provides a second gear or a park lock state of the transmission.