Divided Shift Shaft Vibration Isolation Mechanism

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional shifting devices for motor vehicle gearboxes transmit vibrations from the transmission to the shift lever, increasing driver discomfort and complexity, while existing solutions to mitigate this either increase costs or complexity.

Innovation Solution

The shifting shaft is divided into two parts, the primary and secondary shafts, which are connected to allow rotation about their longitudinal axis with play, preventing the transmission of oscillations and vibrations through a radial coupling mechanism involving a sleeve and securing element.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a one-piece shift shaft is used, then the structure is simple and cost-effective, but vibrations are transmitted from the transmission to the shift lever

Engineering Contradiction:
Improveshift shaft structureVSAvoidvibration transmission
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The shift shaft is divided into two separate shafts: a primary shift shaft connected to the shift lever and a secondary shift shaft connected to the transmission. This segmentation breaks the direct vibration transmission path while maintaining the functional connection through a coupling mechanism with intentional clearance.

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If a damping element is added to the shift weight, then vibration transmission is reduced, but the complexity and cost increase

Engineering Contradiction:
Improvevibration transmissionVSAvoidshifting device structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The coupling mechanism between the primary and secondary shafts acts as an intermediary element. The intentional clearance in this coupling serves as a passive vibration isolator, allowing relative movement that absorbs vibrations without requiring active damping components or increasing overall device complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If the shift shaft is divided into two parts with rigid connection, then vibration transmission is reduced, but the structure becomes more complex and costly

Engineering Contradiction:
Improvevibration transmissionVSAvoidmanufacturing cost
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The coupling between the two shafts features localized clearance specifically at the connection point, while maintaining rigid connections elsewhere. This allows vibration isolation only where needed (at the interface between primary and secondary shafts) without requiring complete redesign of the entire shaft structure, keeping manufacturing costs reasonable.

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design effectively suppresses the transmission of vibrations to the shift lever, enhancing user comfort without increasing production costs or complexity.

Implementation Method 1

the primary shaft and the secondary shaft are connected to each other in such a way that there is play allowing rotation about the longitudinal axis... This measure largely suppresses, or at least weakens, the transmission of oscillations and vibrations

Methodology Applied
Scientific EffectVibration isolation through clearance: Damping

Data Source

PatentEP3114374B1Shifting device
Publication Date: 2020.02.26 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP3114374B1 patent drawingFigure 1
  • EP3114374B1 patent drawingFigure 2
  • EP3114374B1 patent drawingFigure 3

AI summary

The invention relates to a switchgear (1) for a transmission of a motor vehicle, having a switching shaft (3), which is movable along the longitudinal axis thereof in a selection direction and rotatable by means of a shift lever (2) around a longitudinal axis thereof in a shifting direction, wherein the switching shaft (3) is designed divided in the longitudinal direction and has a primary shaft (11), permanently connected to the shift lever (2), and a secondary shaft (12), permanently connected to at least one shifting sleeve (9) and/or to at least one locking sleeve, wherein the primary sleeve (11) and secondary shaft (12) are connected to each other such that there is play enabling a rotation around the longitudinal axis.