Gearbox Actuation Mechanism for Silent Reverse Gear Engagement

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Solution Overview

Problem

Existing gearbox actuation devices face challenges in smoothly engaging the reverse gear, often resulting in metallic squealing noises due to misalignment of gear wheels, and require complex modifications or additional components, making them costly and difficult to implement on existing gearboxes.

Innovation Solution

The device incorporates a mechanism with a first operative configuration that temporarily displaces the selection mask to halt the primary shaft's rotation, allowing silent engagement of the reverse gear, and a second configuration to recall the mask, using a rocker and locking member to synchronize forward gears and enable regular reverse gear engagement without significant modifications to existing components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a conventional gearbox actuation device is used, then the structure is simple, but the reverse gear engagement produces metallic squealing noises due to misalignment

Engineering Contradiction:
Improvemetallic squealing noise during reverse gear engagementVSAvoidcomplexity of actuation device
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The selection mask is temporarily displaced to a first position before the reverse gear engagement is completed. This preliminary displacement halts the primary shaft rotation in advance, creating optimal conditions for silent reverse gear engagement without requiring complex active control systems

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The selection mask acts as an intermediary element between the control shaft and the actuation members. By temporarily displacing the selection mask to the first position, it mediates the engagement process to halt primary shaft rotation and enable silent reverse gear engagement

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If complex modifications are made to existing gearbox components to enable smooth reverse gear engagement, then the noise is reduced, but the implementation cost and difficulty increase

Engineering Contradiction:
Improvenoise during reverse gear engagementVSAvoidease of implementation on existing gearbox
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The selection mask performs multiple functions: it selects actuation members during normal operation and temporarily displaces to a first position to halt primary shaft rotation during reverse gear engagement. This multi-functionality eliminates the need for separate noise-reduction mechanisms

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

Solution Approach 2:

The existing selection mask and guide means are utilized to achieve silent reverse gear engagement through temporary displacement to a first position, rather than requiring additional dedicated components. The system uses its own elements to solve the noise problem

Inventive Principle:
Principle #25Self-service

3Device complexity

If the selection mask follows the rotation of the control shaft during gear engagement, then the mechanism is simple, but the reverse gear cannot be engaged smoothly

Engineering Contradiction:
Improvesimplicity of mechanismVSAvoidsmoothness of reverse gear engagement
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The guide means is configured to temporarily displace the selection mask to a first position before reverse gear engagement is completed. This preliminary displacement ensures the primary shaft is halted and gear wheels are properly aligned, guaranteeing smooth engagement

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The guide means acts as an intermediary that controls the movement path of the selection mask. It temporarily displaces the mask to a first position during reverse gear engagement, mediating between the simple rotational movement and the requirement for smooth engagement

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3002485B1Device for the selection and the displacement of actuation members of a gearbox for motor-vehicles
Publication Date: 2017.04.19 FIAT GRP AUTOMOBILES
  • EP3002485B1 patent drawingFigure 1
  • EP3002485B1 patent drawingFigure 2
  • EP3002485B1 patent drawingFigure 3

AI summary

The invention regards a device (100) for the selection and the displacement of actuation members (26, 30, 35, 41) of a gearbox (4) for motor vehicles that comprises a plurality of forward gear ratios (I, II, III, IV, V, VI) and a reverse gear ratio (RM), each associated to a respective actuation member (26, 30, 35, 41). The device (100) includes a mechanism (101) for the assistance to the engagement of the reverse gear (RM).