Gear Wheel Elastomer Track for Acoustic Damping

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Solution Overview

Problem

Existing solutions fail to effectively reduce low-frequency acoustic emissions in balancer shaft gears of reciprocating internal combustion engines, as measures like helical gearing and backlash reduction are inadequate for low-frequency noise, and elastic supports with elastomers are prone to damage and detachment under impulse loads.

Innovation Solution

A gear wheel design featuring a U-shaped elastomer track between the ring gear and hub part, providing a soft radial rigidity to decouple impulse paths and reduce bearing forces, with a silicone elastomer and sintered materials for durability and acoustic damping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If conventional elastic supports with elastomers are used to reduce bearing forces, then bearing forces are reduced, but the elastomer is destroyed through cracking under impulse loads

Engineering Contradiction:
Improvebearing forcesVSAvoidelastomer durability
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The elastomer is pre-compressed between the ring gear and hub part during assembly, creating a pre-load that allows it to absorb subsequent impulse loads without exceeding its elastic limits. This beforehand cushioning prevents the elastomer from being destroyed by sudden force peaks during operation.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The elastomer is selected with specific material parameters (shore hardness 50-90, tensile strength ≥10 MPa, elongation at break ≥50%) to optimize its ability to withstand impulse loads. By carefully selecting and controlling these material parameters, the elastomer achieves both the softness needed for force reduction and the strength needed for durability.

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If the elastomer is made softer to reduce bearing forces, then acoustic emissions are reduced, but the elastomer detaches from gear wheel components in lubricant mist

Engineering Contradiction:
Improveacoustic emissionsVSAvoidelastomer attachment
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The solution combines the elastomer with mechanically robust components (ring gear and hub part made of steel or sintered material). This composite structure allows the elastomer to provide acoustic damping while the rigid components maintain structural integrity and prevent detachment in the lubricant mist environment.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The elastomer is selected with specific material parameters (shore hardness 50-90, tensile strength ≥10 MPa, elongation at break ≥50%) to optimize its ability to withstand impulse loads. By carefully selecting and controlling these material parameters, the elastomer achieves both the softness needed for force reduction and the strength needed for durability.

Inventive Principle:
Principle #35Parameter changes

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 significantly reduces acoustic emissions by minimizing bearing forces and preventing stress peaks, ensuring the gear wheel's longevity and effective torque transmission, even in a lubricant mist environment.

Implementation Method 1

a soft radial rigidity of the elastomer (4)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The U-shaped cross section of the elastomer (4) ensures durability, in particular when operating in a mist of lubricant. The ring gear (3) of the gear wheel (1) is guided by an elastomer track (4) on the hub part (2) of the gear wheel (1)

Methodology Applied
Scientific EffectHysteresis: Hysteresis

Data Source

PatentEP2781791B1Gear wheel
Publication Date: 2016.11.30 BAYERISCHE MOTOREN WERKE AG
  • EP2781791B1 patent drawingFigure 1
  • EP2781791B1 patent drawingFigure 2~3
  • EP2781791B1 patent drawingFigure 4~5

AI summary

The gear wheel (1) is coaxially separated by a gap in a hub portion and a ring gear, where the gap is filled with an elastomer. The gear wheel takes place on a hub-portion side or sprocket-side, where a cross section of the elastomer partially encloses the circumference of an U-shape on a drive side or output side of a drive portion or an output portion. The elastomer is a silicone material.