Annular Cartridge Elastomer Damper for FEAD Torsional Vibration
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Solution Overview
Problem
Existing torsional vibration dampers are not designed to address the complexities introduced by start-stop systems in vehicle engines, such as impact forces and potential slip in the elastomer-metal interface, and require mold-bonding of isolator springs, which adds manufacturing expense and complexity.
Innovation Solution
The design incorporates an annular cartridge with C-shaped or U-shaped grooves housing elastomer members in compression between the hub and other components, eliminating the need for a bearing system and mold-bonding by using a stiff annular cartridge to exert hydrostatic pressure and maintain component alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional mold-bonding is used to attach isolator springs, then the isolator system can be assembled, but manufacturing expense and process complexity increase
Solution Approach 1:
The patent extracts the isolator spring from the mold-bonding process entirely. Instead of mold-bonding the spring to the hub, the spring is inserted into a recess in the hub after the hub is formed, eliminating the need for specialized mold-bonding equipment and processes while maintaining reliable assembly
Solution Approach 2:
The isolator assembly is segmented into separate components: the hub with its recess, the isolator spring as a separate element, and the pulley body. This segmentation allows each component to be manufactured independently using standard processes, then assembled without complex bonding operations
2Reliability
If soft torsional stiffness isolator springs are used, then torsional vibration damping is achieved, but axial and radial stability deteriorates requiring bearing systems
Solution Approach 1:
The patent applies local quality by providing structural support only where needed: the bearing surface is provided locally at the interface between the pulley body and the hub flange, specifically at the region where axial and radial loads are applied. This localized support allows the isolator spring to remain soft for torsional damping while the bearing surface provides stability where required
3Stability of the object's composition
If bearing systems are added to protect isolator springs from axial motion, then axial stability is improved, but device complexity increases
Solution Approach 1:
The patent merges the bearing function directly into the hub structure. The bearing surface is formed as an integral part of the hub flange, combining the support function with the existing structural component rather than adding a separate bearing assembly. This eliminates the need for additional bearing parts while maintaining axial stability
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
This configuration enhances stability and reduces manufacturing costs by eliminating the need for mold-bonding and bearing systems, while effectively addressing torsional vibrations and maintaining axial and radial run-outs in the FEAD system.
Implementation Method 1
an elastomer member seated in each of the one or more annular grooves in compression between the hub and a component for rotation with the hub
Implementation Method 2
using a stiff annular cartridge to exert hydrostatic pressure and maintain component alignment
Data Source
AI summary
Torsional vibration dampers for FEADs are disclosed that include a hub having a sleeve defining a bore for receiving a shaft and an outer annular ring spaced radially outward from the sleeve, thereby defining an annular receptacle, a component for rotation with the hub having an inner annular ring disposed between the sleeve and the outer annular ring of the hub, and an annular cartridge seated in the annular receptacle between the inner annular ring of the component for rotation with the hub and the sleeve or outer annular ring of the hub. The annular cartridge defines a first annular groove having a generally C-shaped or U-shaped cross-sectional profile open radially outward, and has a first elastomer member seated therein in compression, thereby operatively coupling the component for rotation with the hub to the hub. The component may be a pulley body or an inertia member.