Gearbox Shift Lever Decoupling Mechanism

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Solution Overview

Problem

Existing motor vehicle gear change transmissions face challenges in decoupling the operator shift lever from the drive train effectively, leading to unnecessary vibration transmission and complex component settings.

Innovation Solution

The operator shift lever is decoupled from the drive train at specific rest positions by spacing the actuating element from the coupling element, minimizing surface contact and using vibration-damping materials or coatings to prevent vibration transmission, allowing for simplified design and reduced haptic feedback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the shift finger is continuously coupled to the shift mouthpiece throughout all positions, then the shifting control is precise and reliable, but vibrations from the drive train are transmitted to the operator shift lever

Engineering Contradiction:
Improveshifting control reliabilityVSAvoidvibration transmission to shift lever
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The coupling between the shift finger and shift mouthpiece is made dynamic rather than static. The shift finger is designed to be displaceable relative to the shift mouthpiece, allowing it to be coupled during shifting operations for precise control, and decoupled during idle positions to prevent vibration transmission. This dynamic coupling state changes based on operational requirements.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The shifting system is segmented into distinct coupling and decoupling zones. The shift finger can engage with the shift mouthpiece only in the shifting area where precise control is needed, while being decoupled in idle positions. This spatial segmentation allows the system to achieve both reliable shifting control and vibration reduction.

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If decoupling units are provided for each shift gate to prevent vibration transmission, then vibration isolation is improved, but the device complexity increases

Engineering Contradiction:
Improvevibration transmission reductionVSAvoidnumber of decoupling units
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

Instead of providing separate decoupling units for each shift gate, the invention merges the decoupling function into a single universal mechanism. The shift finger's displaceable design serves all shift gates simultaneously, reducing the number of components while achieving the same vibration isolation effect across all gears.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The displaceable shift finger serves multiple functions: it acts as the shifting actuator during gear changes and as a vibration isolator during idle positions. This single component performs both the shifting operation and the decoupling function for all shift gates, eliminating the need for multiple specialized decoupling units.

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

3Stability of the object's composition

If the shift finger is spring-loaded against axial walls to minimize play in neutral position, then the neutral position stability is improved, but the setting complexity and component pairing requirements increase

Engineering Contradiction:
Improveneutral position stabilityVSAvoidsetting and pairing complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The shift finger's displaceable design allows it to self-adjust and self-center in the neutral position through its own elastic deformation and geometric constraints. The finger naturally finds its stable position without requiring external spring loading or complex adjustment mechanisms, achieving neutral position stability through its inherent design properties.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2888511B1Shifting device of a motor vehicle speed-change gearbox
Publication Date: 2020.03.04 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP2888511B1 patent drawingFigure 1
  • EP2888511B1 patent drawingFigure 2~3

AI summary

The invention relates to a shifting device (1) of a motor vehicle speed-change gearbox having a shift rod (3), a pivotable lever (4, 5) which has an actuating element (15) by means of which the shift rod (3) or a shifting element disposed on the shift rod is translationally movable and a coupling element (16) which is disposed on the shift rod (3) so as to not move axially and on which the actuating element (15) engages. The invention is characterized in that in at least one rest position the actuating element (15) is spaced apart from the coupling element (16) or in that in at least one rest position the actuating element (15) and the coupling element (16) have a contact surface which is minimal with regard to the possible positions of the actuating element (15).