Internal-Groove Bellows for Even Force Distribution and Sealing

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Solution Overview

Problem

Existing bellows designs for trilobe constant velocity joints suffer from issues such as binder breakage and uneven force distribution leading to sealing problems due to their massive fastening areas and uneven material thickness.

Innovation Solution

The bellows design incorporates inner and outer grooves in the lobe and guide regions with varying depths and cross-sections, along with reinforcing ribs, to ensure even force distribution and prevent material bending or breakage during fastening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the fastening area is designed massively with uniform material thickness, then the structural strength is improved, but the binder may break during fastening or cause sealing problems due to uneven force distribution

Engineering Contradiction:
Improvestructural strengthVSAvoidbinder reliability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The bellows features variable material thickness in the first fastening region, with connecting regions having lower material thickness than lobe regions and guide regions. This local differentiation allows the thicker lobe and guide regions to bear more force while thinner connecting regions reduce stress concentration, preventing binder breakage while maintaining overall structural strength.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The first fastening region is segmented into functionally distinct zones: lobe regions with higher material thickness for strength, guide regions with higher material thickness for guidance, and connecting regions with lower material thickness for stress relief. This segmentation enables differentiated force distribution across the fastening area.

Inventive Principle:
Principle #1Segmentation

2Reliability

If parallel slots are provided in the trilobal areas, then the sealing capability is improved, but the free-standing rib between slots may bend if material is too soft or cause binder breakage if material is too hard

Engineering Contradiction:
Improvesealing capabilityVSAvoidrib strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

Inner grooves are provided specifically in the lobe regions and guide regions where high strength is needed, while connecting regions maintain lower material thickness. This local differentiation allows the rib structures between slots to have adequate strength in critical areas while maintaining sealing capability through the groove design.

Inventive Principle:
Principle #3Local quality

3Reliability

If the material thickness is reduced in connecting regions, then the force distribution becomes more even, but the overall structural strength may be compromised

Engineering Contradiction:
Improveforce distribution uniformityVSAvoidoverall structural strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The bellows employs variable material thickness where connecting regions have reduced thickness for even force distribution, while lobe regions and guide regions maintain higher thickness for structural strength. This localized quality differentiation resolves the contradiction between uniform force distribution and overall strength.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3568604B2Bellows comprising at least one internal groove
Publication Date: 2025.09.24 GKN DRIVELINE INT GMBH
  • EP3568604B2 patent drawingFigure 1~2
  • EP3568604B2 patent drawingFigure 3
  • EP3568604B2 patent drawingFigure 4~5

AI summary

The aim of the invention is to provide a bellows with an improved sealing action. For this purpose, a bellows is provided which comprises a first and a second fastening region and a bellows region located between the first and the second fastening region, wherein the first fastening region comprises lobe regions and/or guiding regions and connection regions and a connector seat region having a connector seat region surface and having an underside opposite the connector seat region surface, wherein at least one internal groove is located on the underside in the lobe regions and/or in the guiding regions.