Manual Gearbox Reverse Shift Interlock for Synchronizer Wear

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Solution Overview

Problem

The existing control systems for motor vehicle gearboxes experience friction and wear issues due to the axial movement of the synchronization sleeve under torque, leading to potential accidental release of engaged gears and synchronizer damage.

Innovation Solution

A control system with an axially offset level on the synchronization sleeve fork and an additional lug on the interlocking key, which shifts the sleeve slightly to counteract torque-induced movement, reducing friction and wear on the synchronizer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the synchronization sleeve is designed with internal teeth to transmit torque and prevent accidental release, then gear engagement reliability is improved, but the sleeve shifts axially under torque causing friction and wear on the synchronizer

Engineering Contradiction:
Improvegear engagement reliabilityVSAvoidfriction and wear on synchronizer
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by introducing a compensating axial offset that counteracts the torque-induced axial movement of the synchronization sleeve. The offset is designed to preemptively counterbalance the shifting force, preventing the sleeve from moving and contacting the synchronizer during torque transmission, thus avoiding friction and wear while maintaining engagement reliability

Inventive Principle:
Principle #9Preliminary anti-action

2Stability of the object's composition

If the synchronization sleeve is made stable to prevent accidental release, then gear engagement reliability is improved, but the sleeve cannot accommodate torque-induced movement without causing synchronizer damage

Engineering Contradiction:
Improvesynchronization sleeve stabilityVSAvoidsynchronizer wear and heat
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by creating a localized axial offset specifically at the synchronization sleeve position that is affected by torque. This offset is introduced only where needed to counteract the axial movement, while leaving the rest of the synchronization mechanism stable and functional, thus preventing synchronizer damage without compromising overall system stability

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3635280B1System for controlling a manual-type gearbox for a motor vehicle
Publication Date: 2022.04.20 PSA AUTOMOBILES SA
  • EP3635280B1 patent drawingFigure 1
  • EP3635280B1 patent drawingFigure 2~3

AI summary

The invention relates to a system for controlling a gearbox comprising a reverse gear pinion (22) which slides to engage with a receiving pinion (24) formed on a particular synchronization sleeve, the control system comprising forks (18, 26, 28, 30), an actuating finger (14) moving transversely to select a fork by engaging in a groove of a bracket (16), and an interlocking key (44) equipped with bosses (46) bearing on the sides of the brackets (16) having a main level, this control system being noteworthy in that the bracket (16) of the fork of the particular synchronization sleeve (26) comprises an axially offset additional level on one side, and in that the interlocking key (44) comprises an additional lug which comes opposite this offset additional level when the reverse gear is engaged.