Overrunning Alternator Decoupling Pulley with Torsion Spring
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Solution Overview
Problem
Existing pulley systems for vehicle engine auxiliary apparatuses, such as alternators, experience significant stress due to torsional impacts from piston firing in multi-cylinder engines, which are not adequately addressed by prior art, leading to reduced component lifespan and belt system stress.
Innovation Solution
A pulley assembly incorporating a one-way overrunning clutch and a torsion spring, with dual ball-bearings, that allows torque transfer while minimizing torsional impacts and enabling free overrun during engine speed changes, reducing stress on the belt and auxiliary apparatuses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a one-way overrunning clutch is used to allow free overrun during sudden engine speed changes, then the stress on the belt system during deceleration is reduced, but the torsional impacts from piston firing are not adequately addressed
Solution Approach 1:
The pulley assembly is divided into two independent functional components: a one-way overrunning clutch mechanism for handling deceleration events, and a damping element with torsion spring for absorbing torsional impacts during normal operation. This segmentation allows each component to specialize in addressing its specific harmful effect without interfering with the other.
Solution Approach 2:
The damping element acts as an intermediary between the belt-driven outer pulley housing and the alternator-driven inner shaft. It absorbs torsional impacts through its viscoelastic material properties and torsion spring, preventing these harmful forces from being transmitted directly to the alternator while allowing the one-way clutch to handle deceleration events independently.
2Object-affected harmful factors
If damping devices are used to reduce torsional impacts, then the effect of harmful torsional impacts is reduced, but the stress on the belt and apparatuses during sudden speed reduction is not adequately addressed
Solution Approach 1:
The pulley assembly is divided into two independent functional components: a one-way overrunning clutch mechanism for handling deceleration events, and a damping element with torsion spring for absorbing torsional impacts during normal operation. This segmentation allows each component to specialize in addressing its specific harmful effect without interfering with the other.
Solution Approach 2:
The damping element acts as an intermediary between the belt-driven outer pulley housing and the alternator-driven inner shaft. It absorbs torsional impacts through its viscoelastic material properties and torsion spring, preventing these harmful forces from being transmitted directly to the alternator while allowing the one-way clutch to handle deceleration events independently.
3Productivity
If a serpentine belt system is used to drive auxiliary apparatuses, then the auxiliary apparatuses can be driven efficiently, but harmful torsional impact forces are transmitted to the auxiliary apparatuses during piston firing
Solution Approach 1:
The damping element acts as an intermediary between the belt-driven outer pulley housing and the alternator-driven inner shaft. It absorbs torsional impacts through its viscoelastic material properties and torsion spring, preventing these harmful forces from being transmitted directly to the alternator while allowing the one-way clutch to handle deceleration events independently.
Solution Approach 2:
The damping element changes the mechanical parameters of the drive system by introducing a compliant element that can deform under torsional load. This changes the stiffness and damping characteristics of the drive system, allowing it to absorb torsional impacts while maintaining efficient power transmission during normal 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 solution effectively reduces torsional impacts and stress on the serpentine belt and auxiliary apparatuses by using a torsion spring to absorb and dampen vibrations, and a one-way overrunning clutch to allow free spinning during sudden engine speed changes, thereby extending component lifespan and reducing belt system stress.
Implementation Method 1
a helical torsion spring, the top end of which is matingly coupled to the inner rotating element and the bottom end of which is matingly coupled to the outer pulley housing, whereby torsional impacts to the pulley assembly are substantially reduced
Implementation Method 2
The invention utilizes a torsion spring which flexes, or winds and un-winds, during such torsional impacts, thereby slowing the accelerative effect on the rotor of the alternator and reducing the stress on the serpentine belt and other components in the belt system
Implementation Method 3
a one-way overrunning clutch disposed between the inner shaft and damping element, the one-way overrunning clutch being configured so as to permit torque to be transferred from the inner rotating element to the inner shaft, and to substantially prevent the transfer of torque from the inner shaft to the inner rotating element
Implementation Method 4
dual ball-bearings
Data Source
AI summary
A pulley assembly for an automobile auxiliary apparatus, such as an alternator, that dampens torsional impacts and reduces the stress on the auxiliary apparatus, the belt drive system and other apparatuses, by use of both a torsion spring and a one-way overrunning clutch mechanism allowing for the free run of the pulley shaft.