Manual Transmission Reverse Gear Vibration Control

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Solution Overview

Problem

Manual transmissions often experience unwanted rattling noises due to torsional vibrations, particularly when load-free gears mesh, leading to undesirable noise issues.

Innovation Solution

The second pinion is decoupled from the additional shaft during non-engagement, and a sliding sleeve is used to influence the moment of inertia of the rotating system, reducing vibrations by being non-rotatably connected to the second pinion when engaged, thereby minimizing rattling noises.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the second pinion is permanently connected to the additional shaft, then the reverse gear function is ensured, but the moment of inertia increases causing rattling noises during torsional vibrations

Engineering Contradiction:
Improvereverse gear functionVSAvoidrattling noises
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies the dynamics principle by making the connection between the second pinion and additional shaft changeable rather than fixed. The gear shift clutch enables the system to dynamically switch between connected and decoupled states, optimizing performance for different operating conditions - connected during reverse gear operation, decoupled during forward gear operation to minimize vibrations

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent segments the connection between the second pinion and additional shaft into controllable portions through the gear shift clutch mechanism. This allows selective engagement and disengagement of the connection, separating the functional requirements of reverse gear operation from the vibration reduction requirements during forward operation

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If the second pinion is decoupled from the additional shaft to reduce rattling noises, then the moment of inertia is reduced, but the reverse gear engagement becomes more complex

Engineering Contradiction:
Improverattling noisesVSAvoidgear shift mechanism
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The gear shift clutch serves multiple functions: it enables reverse gear engagement by connecting the second pinion to the additional shaft, and simultaneously acts as a vibration reduction mechanism by decoupling them during forward gear operation. This multi-functionality reduces the need for separate dedicated components for each function

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

3Object-affected harmful factors

If a sliding sleeve is added to control the connection between the second pinion and additional shaft, then rattling noises are reduced, but the device complexity increases

Engineering Contradiction:
Improverattling noisesVSAvoidsliding sleeve mechanism
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the vibration reduction function with the existing gear shift mechanism by integrating the sliding sleeve into the gear shift clutch assembly. The sliding sleeve's axial movement to connect or decouple the second pinion is combined with the gear shifting operation, so that a single operational action achieves both gear change and vibration control

Inventive Principle:
Principle #5Merging (Combining)

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 configuration effectively reduces rattling noises by altering the moment of inertia of the vibration system, making the transmission simpler and more compact while maintaining operational efficiency.

Implementation Method 1

a sliding sleeve is used to influence the moment of inertia of the rotating system, reducing vibrations by being non-rotatably connected to the second pinion when engaged

Methodology Applied
Scientific EffectMoment of inertia: Moment of Inertia

Data Source

PatentEP3198170B1Transmission for a motor vehicle
Publication Date: 2020.02.12 GETRAG FORD TRANSMISSIONS GMBH
  • EP3198170B1 patent drawingFigure 1
  • EP3198170B1 patent drawingFigure 2
  • EP3198170B1 patent drawingFigure 3

AI summary

The invention relates to a transmission for a motor vehicle, comprising an input shaft (10) and an output shaft (30), fixed gears (11 to 16), idler gears (31 to 36), and gear couplings (37, 40, 41) for the rotationably fixed connection of the idler gears (31 to 36) to the input shaft (10) or the output shaft (30), a plurality of gears (I to VI), wherein one of the idler gears (31 to 36) and one of the gear couplings (37, 40, 41) is assigned to each gear. The idler gear is connected in a rotatably fixed manner to the shaft bearing the idler gear by way of the gear coupling, whenever the corresponding gear is engaged. The transmission further comprises a ring gear (2) meshing with a first pinion (39) arranged on the output shaft (30), an additional shaft (50), on which a second pinion (52) that meshes with the ring gear (2), an additional toothed gear (51), and an additional gear coupling (53) are arranged, wherein the additional shaft (50) and the additional gear coupling (53) are assigned to an additional gear. The transmission is characterized in that the second pinion (52) is rotatably arranged on the addition shaft (50), and when the additional gear engaged, is connected to the second pinion (52) in a rotationally fixed manner.