Rolling Boot Compact Design Reducing Grease Pressure

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Solution Overview

Problem

Existing rolling boots have a large overall height, which is a disadvantage in space-restricted applications like automobiles, and they have high stiffness due to specific design features that are necessary to withstand centrifugal forces and grease pressure.

Innovation Solution

A rolling boot system with a transition region between the fastening and fold regions, featuring a specific geometry with an angle between 90° to 120° and a fold trough depth of up to 65% of the fold height, along with outer ribs that protrude to form positioning and bearing surfaces, reducing the boot's inside diameter and grease pressure while maintaining structural rigidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the rolling boot has a large overall height, then it can accommodate the fastening regions and fold region with sufficient structural rigidity, but it increases the space requirements which is disadvantageous in space-restricted applications

Engineering Contradiction:
Improvestructural rigidityVSAvoidoverall height
Core Design Contradiction:
StrengthVSLength of moving object

Solution Approach 1:

The patent applies parameter changes by optimizing the fold region geometry, specifically setting the fold trough depth to at most 65% of the fold height and the angle between the base surface and outer side of the first fold flank to 90°-120°. These parameter optimizations allow the boot to achieve sufficient structural rigidity while reducing the overall height and inside diameter, resolving the contradiction between strength and compact dimensions.

Inventive Principle:
Principle #35Parameter changes

2Strength

If the rolling boot has high stiffness to withstand centrifugal forces and grease pressure, then it can maintain structural integrity under load, but it increases the overall height and reduces adaptability to space-restricted applications

Engineering Contradiction:
ImprovestiffnessVSAvoidadaptability to space-restricted applications
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The patent optimizes geometric parameters including the fold trough depth (at most 65% of fold height) and the angle between base surface and fold flank (90°-120°), which enables the boot to achieve adequate stiffness for withstanding centrifugal forces and grease pressure while maintaining a compact overall height suitable for space-restricted automotive applications.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a transition region with a base surface that is offset axially with respect to the housing part and displaced with respect to the main axis of the boot. This dimensional repositioning allows the boot to achieve the required structural rigidity through optimized spatial arrangement rather than increased height, improving adaptability to space-constrained environments.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Stress or pressure

If the rolling boot has a reduced inside diameter, then it reduces grease pressure acting on the boot, but it requires precise geometric control of the fold region to maintain structural rigidity

Engineering Contradiction:
Improvegrease pressureVSAvoidgeometric control of fold region
Core Design Contradiction:
Stress or pressureVSManufacturing precision

Solution Approach 1:

The patent specifies precise geometric parameters for the fold region, including fold trough depth (at most 65% of fold height) and the angle between base surface and outer side of the first fold flank (90°-120°). These controlled parameters enable the boot to achieve reduced inside diameter and lower grease pressure while maintaining sufficient structural rigidity through optimized geometry.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2288819B1system consisting of a housing and a rolling boot
Publication Date: 2014.10.08 GKN DRIVELINE INT GMBH
  • EP2288819B1 patent drawingFigure 1~3
  • EP2288819B1 patent drawingFigure 4~5

AI summary

To achieve the object of making available a rolling boot which is of compact design, there is proposed a rolling boot having a first fastening region and a fold region with at least a first fold having a first fold peak region and a first fold flank near the first fastening region and, opposite this first fold flank, a second fold flank which is adjoined by a fold trough, wherein a transition region having a base surface is arranged between the first fastening region and fold region, and an angle a having a range from approximately 90° to approximately 140° is formed between the base surface and an outer side of the first fold flank, and the fold trough has a depth T which is at most approximately 65 percent of a height H of the first fold.