Transmission Joint Bellows Structure for Flexibility Without Buckling

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Solution Overview

Problem

Existing bellows for transmission joints face issues with buckling and undesired deformation, particularly when the outer and inner joint members are at large angles, despite the use of reinforcing ribs and specific fold designs.

Innovation Solution

A bellows design featuring a hollow tubular body with fastening regions of differing diameters, interconnected by a deformable wall with a stiffening collar or extension section, ensuring flexibility and preventing buckling through controlled deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the bellows is designed with a deformable wall to provide flexibility for large joint angles, then the flexibility is improved, but buckling and undesired deformation occur

Engineering Contradiction:
ImproveflexibilityVSAvoidbuckling resistance
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The bellows structure implements different properties in different regions: the fold region has enhanced stiffness through reinforcing ribs to prevent buckling, while the extension sections maintain flexibility for joint movement. This local differentiation resolves the contradiction between overall flexibility and local buckling resistance.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The bellows combines materials with different properties - a stiffening collar made of stiff material (such as metal or rigid plastic) is integrated with the flexible bellows body (rubber or elastomer). This composite structure provides both the flexibility needed for joint movement and the stiffness required to prevent buckling in the fold region.

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If reinforcing ribs are added to prevent buckling, then the buckling resistance is improved, but the device complexity increases

Engineering Contradiction:
Improvebuckling resistanceVSAvoidstructural complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The bellows is divided into distinct functional sections: fold regions with reinforcing ribs for buckling prevention, extension sections for flexibility, and end sections for mounting. This segmentation allows each region to be optimized independently, providing buckling resistance where needed without unnecessarily complicating the entire structure.

Inventive Principle:
Principle #1Segmentation

3Stability of the object's composition

If the fold region is designed with specific forms and dimensions to prevent buckling, then the buckling resistance is improved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvebuckling resistanceVSAvoidfold geometry precision
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The bellows is pre-formed during manufacturing with predetermined fold patterns, extension section lengths, and reinforcing rib positions. This preliminary structuring ensures that the critical geometric parameters for buckling resistance are built-in during production, reducing the need for high-precision adjustments during assembly and operation.

Inventive Principle:
Principle #10Preliminary action

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 design achieves improved flexibility and effectively prevents buckling, protecting transmission components by maintaining a sealed inner space and preventing lubricant leakage.

Implementation Method 1

a deformable wall (30) which interconnects the two fastening regions and forms at least one fold between the two fastening regions

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

A bellows design featuring a hollow tubular body with fastening regions of differing diameters, interconnected by a deformable wall with a stiffening collar or extension section, ensuring flexibility and preventing buckling through controlled deformation

Methodology Applied
Scientific EffectStructural reinforcement:

Implementation Method 3

The bellows forms an inner space that is closed to the surroundings so that no dirt can enter the transmission joint. In addition, the inner space can be filled with a lubricant and no lubricant can leave the inner space

Methodology Applied
Scientific EffectPhysical containment: Physical Containment

Data Source

PatentEP4437241B1Bellows for protection of transmission joint
Publication Date: 2026.04.15 NEAPCO INTELLECTUAL PROPERTY HOLDINGS LLC
  • EP4437241B1 patent drawingFigure 1
  • EP4437241B1 patent drawingFigure 2
  • EP4437241B1 patent drawingFigure 3

AI summary

Bellows (10) for the protection of parts of a transmission joint (40), wherein the bellows (10) is in the form of a hollow tubular body that is open at each of its ends and has a fastening region (21;22) at each of its open ends. The two fastening regions (21;22) have cross-sections with different outer diameters and run essentially in parallel to a longitudinal axis (X) of the bellows (10), and these end side fastening regions (21;22) are interconnected by a deformable wall (30) that runs transverse to the longitudinal axis (X) of the bellows (10), wherein the deformable wall (30) forms at least one fold (32) between the two fastening regions (21;22). Thereby, a first fastening region (21) with the larger outer diameter D is extended in the direction of a second fastening region (22) with the smaller outer diameter d by means of a circumferential extension section (50) with a circular free edge (51) and the deformable wall (30) is connected to this extension section (50) at a first connection line (60) which is located before the free edge (51) of the extension section (50). The outer surface of the extension section (50) is straight at least between the first connection line (60) and the free edge (51).