Interlocked Crankshaft Damper Isolator for Start-Stop Vibration
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Solution Overview
Problem
Existing torsional vibration dampers for vehicle engines are not designed to handle the complexities introduced by start-stop systems, leading to issues like potential slip in the elastomer-metal interface and transmission of rigid body mode vibrations, which can cause wear and damage to the front end accessory drive system, and they require costly mold-bonding processes and multiple moving components.
Innovation Solution
A crankshaft damper-isolator design that includes a hub, pulley body, elastomeric or torsion spring isolator members, and a slide bearing, which eliminates the need for mold-bonding and reduces the number of components, allowing for easier manufacturing and assembly while effectively isolating vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional mold-bonded isolators are used, then vibration isolation is achieved, but manufacturing cost and complexity increase due to special equipment and time requirements
Solution Approach 1:
The isolator member is integrated as a single piece with both isolator portions formed as one continuous elastomeric component, eliminating the need for separate mold-bonding operations to attach isolators to the hub and pulley body. This merging of functions into a single component reduces manufacturing steps and costs while maintaining vibration isolation effectiveness.
2Reliability
If multiple moving components are used in the isolator system, then vibration isolation is achieved, but device complexity and overall cost increase
Solution Approach 1:
The isolator member combines multiple functional elements into a single integrated component that performs both isolator functions simultaneously, reducing the number of separate moving parts while maintaining effective vibration isolation across different operating conditions.
Solution Approach 2:
The single isolator member is designed with different portions that perform different isolator functions - one portion handles normal operating vibrations while another portion addresses impact forces from belt starts, making the component multi-functional and reducing overall system complexity.
3Use of energy by moving object
If start-stop systems are implemented to conserve fuel, then fuel consumption is reduced, but impact forces and rigid body mode vibrations increase causing wear and damage to FEAD components
Solution Approach 1:
The isolator member is positioned and designed to provide cushioning protection before impact forces occur during belt start events. The elastomeric material absorbs and dampens impact forces from belt starts and rigid body mode vibrations before they can transmit to the hub and pulley body, preventing wear and damage to FEAD components.
Solution Approach 2:
The isolator member converts harmful impact forces and vibrations from start-stop operation into beneficial damping effects. The elastomeric material transforms the mechanical energy of impact forces into heat through internal friction, protecting the metallic components while enabling fuel-efficient start-stop operation.
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 design reduces manufacturing costs, minimizes component complexity, and effectively mitigates rigid body mode vibrations, enhancing the durability of the front end accessory drive system by absorbing and damping torsional frequencies without the need for mold-bonding.
Implementation Method 1
an elastomeric isolator member in an uncompressed state between the hub and the pulley body
Implementation Method 2
The isolator member is engaged with both the hub and the face guard for rotation therewith... effectively isolating vibrations
Implementation Method 3
a torsion spring isolator seated in the annular receptacle of the hub
Implementation Method 4
a torsion spring isolator... for counteracting torque to the crank, negating the torque twisting amplitude
Implementation Method 5
a slide bearing disposed between the outer radial surface of the hub and the sleeve of the pulley body... allows the pulley body to rotate relative to the hub
Data Source
AI summary
Torsional vibration dampers having isolator members (crankshaft damper-isolators) are disclosed that include a hub defining an annular receptacle, a pulley body having a belt engaging surface, a damper assembly disposed between an outermost radial surface of the hub and the pulley body, an isolator member seated in the annular receptacle of the hub, and a slide bearing disposed between an outer radial surface of the hub and the sleeve of the pulley body. The isolator member is engaged with both the hub and the pulley body for rotation therewith when the hub and pulley body rotate at the same speed and when the hub rotates relative to the pulley body. The isolator member may be an elastomeric isolator or a torsion spring isolator. The slide bearing axially retains the pulley body to the hub and allows the pulley body to rotate relative to the hub.