Rolling Boot Transition Region for Form Stability
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Solution Overview
Problem
Existing rolling boots used in joints, such as ball-and-socket or trilobe joints, face issues with decreased form stability at higher revolutions per minute, leading to the need for additional retention rings and shaft spring means to prevent disassembly, and they are not effective in withstanding grease pressure.
Innovation Solution
A rolling boot design with a first transition region having a specific flange arrangement and angle configuration between the fastening region and the fold, providing increased form stability through a radial symmetric embodiment and optimized diameter ratios, which allows for higher retention forces without the need for additional retention rings or spring means.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the rolling boot has a compact design with reduced inside diameter to withstand grease pressure, then grease pressure resistance is improved, but form stability decreases at higher revolutions per minute
Solution Approach 1:
The rolling boot is divided into distinct functional regions: a first fastening region, a first transition region with specific angle configuration (30° to 89.8°), a fold region, a second transition region, and a second fastening region. This segmentation allows each region to be optimized independently - the transition regions provide structural support for form stability while the compact fold region withstands grease pressure.
Solution Approach 2:
Different regions of the rolling boot are given different geometric properties and thickness characteristics. The first transition region has a specific angle configuration and diameter ratio (D1:D2 of 1:1.01 to 1:1.25) to provide form stability, while the fold region maintains a reduced inside diameter for grease pressure resistance. This local differentiation resolves the contradiction between overall form stability and grease pressure resistance.
2Reliability
If additional retention rings and shaft spring means are added to prevent disassembly, then joint retention is improved, but device complexity increases
Solution Approach 1:
The rolling boot integrates multiple functions into a single component: it provides sealing, retains grease, and crucially, the first transition region with its specific angle configuration and diameter ratio provides form stability and retention forces that eliminate the need for separate retention rings and spring means. This merging reduces device complexity while maintaining joint retention.
Solution Approach 2:
The first transition region serves multiple purposes: it acts as a structural support element providing form stability at high RPM, generates retention forces to prevent disassembly, and maintains the compact geometry needed for grease pressure resistance. This multi-functionality replaces what would traditionally require separate retention components.
3Strength
If the first fold has a sharp nose design with specific angle configuration, then grease pressure withstanding capability is improved, but form stability at high RPM decreases
Solution Approach 1:
The invention optimizes specific geometric parameters of the transition regions, particularly the angle α (30° to 89.8°) and the diameter ratio D1:D2 (1:1.01 to 1:1.25). These parameter changes create an optimal balance where the first transition region provides sufficient form stability at high RPM while the fold region maintains the sharp nose design for grease pressure resistance.
Data Source
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AI summary
In order to provide for a rolling boot showing increased form stability compared to rolling boots known from the state of the art, such a rolling boot is suggested comprising a first fastening region (12) for fastening the boot to a joint casing (82), a second fastening region (14) for fastening the boot to a shaft (74), and a fold region (16) between the first and the second fastening region with a first fold (22) near to the first fastening region (12) and a second fold (24) near to the second fastening region (14), wherein it comprises further between the first fastening region (12) and the first fold (22) a first transition region (18) comprising a first flange (26) neighbouring the first fastening region (12) with a bottom (38), wherein a ratio between a first minimal diameter Dj, defined by the bottom (38) of the first flange of the first transition region, and a second maximal diameter D2, defined by the first fold (22), both if viewed in a longitudinal section direction along the main axis, is between approximately 1:1.01 to approximately 1:1.25.