Vehicle Transfer Damper Spline Coupling Noise Reduction

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Solution Overview

Problem

Four-wheel drive vehicles experience teeth rattling noise due to drivetrain resonance with engine torque variations, which is not effectively reduced without increasing fuel consumption or compromising damper durability.

Innovation Solution

A transfer structure with a damper and spline-fitted sections on the main-drive-wheel output shaft, where the damper transmits torque directly when it's high and via the damper when it's low, preventing excessive torque application and reducing size, thereby minimizing noise and maintaining durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the torque distribution to the front wheels is increased to reduce drivetrain resonance and teeth rattling noise, then the rattling noise is reduced, but the drive loss and fuel consumption increase

Engineering Contradiction:

Improveteeth rattling noiseVSAvoidfuel consumption

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

A damper is introduced as an intermediary component between the coupling and the transmission mechanism. The damper absorbs vibrations and reduces drivetrain resonance, thereby reducing teeth rattling noise without requiring increased torque distribution to the front wheels, thus avoiding increased fuel consumption

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If a damper is disposed between the coupling and the transmission mechanism to reduce vibration, then the teeth rattling noise is reduced, but the damper durability degrades due to excessive torque application

Engineering Contradiction:

Improvedrivetrain vibrationVSAvoiddamper durability

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The damper is positioned at a specific location between the coupling and the transmission mechanism where it can effectively absorb vibrations without being subjected to excessive torque. The local structural design ensures the damper receives only the necessary vibration damping function while avoiding overload that would compromise its durability

Inventive Principle:

Principle #3Local quality

3Reliability

If the rigidity of the elastic member of the damper is enhanced to improve damper durability, then the damper durability is improved, but the vibration of the drivetrain cannot be suitably reduced

Engineering Contradiction:

Improvedamper durabilityVSAvoiddrivetrain vibration

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The rigidity parameter of the elastic member is optimized to an appropriate level rather than being excessively enhanced. This parameter change allows the damper to effectively reduce drivetrain vibration while maintaining sufficient durability, avoiding the trade-off between over-rigidification and vibration reduction capability

Inventive Principle:

Principle #35Parameter changes

4Power

If the coupling is completely engaged to transmit torque to the front wheels, then the four-wheel drive state is achieved, but the drivetrain resonance and teeth rattling noise occur when torque is low

Engineering Contradiction:

Improvetorque transmissionVSAvoiddrivetrain resonance

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The damper serves as an intermediary that decouples the direct torque transmission path from the vibration transmission path. It allows torque to be transmitted to the front wheels while simultaneously absorbing vibrations and reducing drivetrain resonance, enabling effective torque transmission without the harmful resonance effects

Inventive Principle:

Principle #24Intermediary (Mediator)

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

The solution effectively reduces teeth rattling noise without increasing fuel consumption and enhances damper durability, while preventing size increase of the transfer device, improving ride comfort and mountability.

Implementation Method 1

a damper disposed on the main-drive-wheel output shaft between the coupling and the transmission mechanism

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Implementation Method 2

The solution effectively reduces teeth rattling noise without increasing fuel consumption and enhances damper durability

Methodology Applied

Scientific EffectVibration damping: Damping

Data Source

PatentUS10513176B2Vehicle transfer structure

Publication Date: 2019.12.24 MAZDA MOTOR CORP

AI summary

A vehicle transfer structure includes a main-drive-wheel output shaft that receives torque from a drive source and outputs it to main drive wheels, a part-time-drive-wheel output shaft provided parallel to the main-drive-wheel output shaft, a coupling provided on the main-drive-wheel output shaft and which partially extracts the torque to the part-time-drive-wheel output shaft via a transmission mechanism, and a damper disposed on the main-drive-wheel output shaft. The coupling is provided with an input-side coupling part coupled to an inner circumferential part of the damper. The input-side coupling part is coupled, via a spline-fitted section, to an output-side coupling part of a drive force transmission member which is coupled to an outer circumferential part of the damper and transmits a drive force to a driving-side transmission member of the transmission mechanism. The spline-fitted section allows a relative rotation between the input- and output-side coupling parts within a given angle.