Pulley Flange Sealing Structure for Compact Contamination Resistance
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Solution Overview
Problem
Pulley devices for tensioner and winding rollers face issues with pollution resistance, requiring additional sealing means to prevent contaminants from entering the bearing chamber, while also needing to be economical, easy to mount, and compact in size.
Innovation Solution
A pulley device design featuring a fixed inner element with a sleeve protruding from its lateral surface, a rotating outer element, and a protective flange with an annular collar and folded tabs to enhance sealing and reduce axial and radial space, incorporating a bearing with coaxial rings and rolling elements, and a mounting bore with distinct diameters to accommodate screws securely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If additional sealing means are added to prevent pollution, then resistance to pollution is improved, but device complexity increases
Solution Approach 1:
The sealing function is merged into the protective flange structure itself. The annular collar forms an integral part of the flange that creates a sealing interface with the fixed inner element, eliminating the need for separate sealing components while maintaining pollution resistance
Solution Approach 2:
The design utilizes a thin annular collar structure that provides effective sealing through its geometric configuration rather than requiring thick or complex sealing materials. The collar's annular shape creates an effective barrier against contaminant ingress
2Volume of moving object
If the design is made more compact, then space requirements are reduced, but ease of assembly deteriorates
Solution Approach 1:
The mounting bore is segmented into two distinct parts: a first bore part for the threaded screw body and a second bore part for the screw head. This segmentation allows for simplified assembly where the screw can be directly inserted and secured, reducing assembly complexity despite the compact overall dimensions
Solution Approach 2:
The mounting bore structure nests the first bore part within the second bore part, creating a compact configuration where the threaded portion and head reception portion are axially adjacent. This nested arrangement minimizes space requirements while maintaining ease of assembly through the straightforward two-part screw mounting process
3Object-affected harmful factors
If protective flange is added, then protection from contaminants is improved, but radial and axial space increases
Solution Approach 1:
The protective flange incorporates a thin annular collar that provides effective contaminant protection through its sealing geometry. The collar's minimal thickness in both radial and axial directions ensures protection from contaminants while maintaining compact overall dimensions of the pulley device
Solution Approach 2:
The protective function is localized to where it is most needed - at the interface between the flange and the fixed inner element. The annular collar provides targeted sealing and protection at this critical interface rather than requiring extensive protective structures throughout the entire device
Data Source
AI summary
A pulley device for a tensioner roller or winding roller of a transmission element, having a fixed inner element configured to receive a screw, a rotating outer element that is mounted to rotate coaxially about the fixed inner element and is intended to cooperate with the transmission element, and an annular protective flange bearing against a lateral surface of the fixed inner element. The fixed inner element provides a sleeve axially protruding from the lateral surface. The flange provides an inner axial portion mounted securely on an outer surface of the sleeve.