Pulley Eccentric Hub Stops Eliminate Dedicated Coupling
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Solution Overview
Problem
Existing pulley devices for automotive belt drive systems require dedicated coupling members for installation, which are specific to each device and must be discarded after use, making manufacturing and installation costly and inefficient.
Innovation Solution
A pulley device with an eccentric adjusting member and a torsion spring, featuring axially projected stops on the hub and a radially outwardly projecting flange for precise positioning, allowing for free pivoting within defined angles and using a standard tool for installation, eliminating the need for a dedicated coupling member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a dedicated coupling member is used for installation, then the pivot structure and eccentric adjusting member can be coupled in a specific relative position, but the device complexity increases and manufacturing cost rises due to the need for custom-made components
Solution Approach 1:
The hub is designed with integrally formed axially projected stops that serve dual purposes: (1) positioning the eccentric adjusting member during installation, and (2) limiting the rotational range of the hub during operation. This eliminates the need for a separate dedicated coupling member, reducing device complexity while maintaining installation precision.
Solution Approach 2:
The positioning function previously performed by a separate coupling member is merged into the hub structure itself through integrally formed stops. This consolidation reduces the number of components and simplifies manufacturing while ensuring precise positioning during installation.
2Ease of operation
If a dedicated coupling member is required for each tensioner, then the installation can be performed, but the loss of substance increases due to the disposal of custom-made coupling members after installation
Solution Approach 1:
The hub's integrally formed stops serve as self-contained positioning and limiting features that remain part of the tensioner assembly after installation. No external coupling members need to be attached and subsequently discarded, eliminating material waste while maintaining installation ease.
Solution Approach 2:
The invention eliminates the need for disposable coupling members by incorporating permanent positioning features (integrally formed stops) into the hub. This transforms a temporary, disposable component into a permanent, reusable feature, reducing substance loss.
3Adaptability or versatility
If the hub and eccentric adjusting member can freely pivot within a large angle, then the belt tensioning adjustment range is improved, but the positioning precision deteriorates due to lack of defined limits
Solution Approach 1:
The hub is designed to freely pivot within a defined angular range limited by integrally formed stops. This dynamic design allows sufficient adjustment range for belt tensioning while maintaining precise positioning through the stop-defined boundaries, optimizing both adaptability and precision.
Solution Approach 2:
The integrally formed stops create an asymmetric angular constraint on the hub's rotation, defining a specific operational range. This asymmetric limitation ensures precise positioning within the tensioning adjustment range, balancing versatility with manufacturing precision.
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 solution enables cost-effective and simplified manufacturing and installation of pulley devices by allowing standard tools to be used, reducing waste and improving installation precision, while maintaining effective belt tensioning.
Implementation Method 1
a torsion spring between the eccentric adjusting member and hub so as to exert a biasing force in a belt-tightening direction
Data Source
AI summary
A pulley device for a belt that includes an eccentric adjusting member fixed on a support, an eccentric hub rotatably mounted on the eccentric adjusting member, a torsion spring between the eccentric adjusting member and hub to exert a biasing force, and a pulley rotatably mounted on the hub. The hub provides an upper radial surface and the eccentric adjusting member provides a radially outwardly projecting flange formed at an upper end of the eccentric adjusting member and forming an axial abutment for the upper radial surface. The upper radial surface provides a pair of axially projected stops formed integrally within, each stop being dedicated to come into abutment against a corresponding stop provided by the radially outwardly projecting flange of the eccentric adjusting member. The hub further provides engaging means adapted to cooperate with an external tool, the engaging means circumferentially located between the projected stops of the hub.