Pulley Protective Flange Structure for Contamination Blocking
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Solution Overview
Problem
Pulley devices for tensioner and winding rollers face issues with pollution ingress, leading to accelerated deterioration of internal components due to worn sealing means, which reduces the service life and quality of the mechanical connection.
Innovation Solution
A pulley device design featuring a protective flange with an annular folded portion that forms a narrow passage to improve sealing between the flange and the pulley, reducing pollution ingress and enhancing the axial and radial space efficiency, while being economical and easy to mount.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If sealing means are provided to close the bearing chamber, then pollution ingress is reduced, but the sealing means wear over time and become less effective
Solution Approach 1:
The patent introduces an intermediary folded portion of the flange that creates a labyrinthine path between the external environment and the bearing chamber. This folded structure acts as a mediator that complicates the pollution ingress path without relying on wear-prone sealing elements, thereby maintaining sealing effectiveness over time.
Solution Approach 2:
The flange is segmented into multiple portions including a folded portion with multiple folds. This segmentation creates multiple barriers and narrow passages that pollution must navigate, effectively reducing pollution ingress without using traditional sealing means that are subject to wear.
2Object-affected harmful factors
If additional sealing means are added to the bearing, then pollution resistance improves, but the device complexity increases
Solution Approach 1:
The flange is designed to serve multiple functions: it provides structural support, acts as a thrust washer for the screw head, and incorporates the folded portion to create sealing barriers. This multi-functionality reduces the need for separate sealing components, thereby reducing device complexity while maintaining pollution resistance.
Solution Approach 2:
The sealing function is merged into the flange structure itself through the folded portion. Instead of adding separate sealing means to the bearing, the flange's folded geometry is combined with the bearing assembly to provide both structural and sealing functions in a unified structure.
3Object-affected harmful factors
If the flange design is modified to improve sealing, then the space requirement increases, but compactness is reduced
Solution Approach 1:
The folded portion of the flange utilizes the axial dimension to create radial sealing barriers. By folding the flange material axially, the design creates multiple radial sealing surfaces without significantly increasing the overall radial or axial envelope of the device, thus blocking pollution while maintaining compactness.
Data Source
AI summary
A pulley device for a tensioner roller or winding roller of a transmission element, having a fixed inner element, a rotating outer element that is mounted to rotate coaxially about the fixed inner element, and an annular protective flange having a substantially radial portion bearing against a front surface of the fixed inner element. The flange includes an annular folded portion extending substantially axially from an outer edge of the flange and passing radially into the immediate vicinity of an axially protruding annular portion of the rotating outer element to form a narrow passage.