Filtering Pulley Labyrinth Lip for Dust-Proof Vibration Damping
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Solution Overview
Problem
Existing filtering pulleys face issues with relative rotation between the crown and hub, dust and debris ingress causing noise and reduced lifespan, and inadequate handling of torsional vibrations in internal combustion engines, particularly at low speeds and with systems like double clutch gearboxes or start-stop systems.
Innovation Solution
A filtering pulley design featuring a hub, annular crown, elastic groups, actuator, and dust protection lip, with a bush having an L-shaped section to manage relative rotation, prevent debris ingress, and absorb axial loads, enhancing sealing and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a filtering pulley is used to reduce torsional vibrations, then vibration filtering is improved, but dust and debris can ingress between hub and crown causing noise and reduced lifespan
Solution Approach 1:
A dust protection lip is introduced as an intermediary element between the hub and crown assembly and the external environment. This lip protrudes radially outward to intercept dust and debris before they can reach the critical interface between hub and crown, thereby protecting the filtering pulley mechanism while maintaining its vibration filtering function
Solution Approach 2:
The dust protection lip is made of elastomeric material, which provides flexibility to accommodate relative rotation between hub and crown while maintaining the sealing function. The elastomeric nature allows the lip to deform and return to its original position, ensuring continuous protection against dust ingress during operation
2Stability of the object's composition
If relative rotation between crown and hub is allowed for filtering function, then vibration filtering is improved, but overrunning moments and noise increase
Solution Approach 1:
The dust protection lip is designed as a separate, removable component that can be independently manufactured and assembled. This allows the lip to be optimized for dust protection without compromising the relative rotation function between hub and crown, effectively separating the dust protection function from the filtering mechanism
Solution Approach 2:
The dust protection lip is made of elastomeric material, combining the properties of flexibility (to allow relative rotation) and sealing (to prevent dust ingress). This composite material approach resolves the contradiction by providing both required functions simultaneously
3Object-affected harmful factors
If sealing between hub and crown is enhanced to prevent dust ingress, then protection against contamination is improved, but assembly complexity increases
Solution Approach 1:
The dust protection lip is designed as a separate segment that can be independently assembled into the filtering pulley. This segmentation allows for simplified manufacturing and assembly, as the lip can be installed as a discrete component rather than requiring complex integrated sealing structures
Solution Approach 2:
The elastomeric dust protection lip automatically seals against the hub and crown through its inherent elasticity, without requiring additional fastening elements or complex assembly procedures. The lip self-adjusts to maintain contact and sealing effectiveness, reducing assembly complexity
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 effectively reduces noise, protects against contamination, and extends the pulley's lifespan by preventing debris entry and managing torsional vibrations, while ensuring smooth operation and easy assembly.
Implementation Method 1
one or more elastic elements through which the torque is transmitted from the hub to the crown
Implementation Method 2
a dust protection lip configured to prevent the contamination from the outside of the rotating support between hub and crown
Data Source
Figure 1~3
Figure 2
Figure 4~5
AI summary
Filtering pulley (1) comprising a hub (2) adapted to be fixed to a rotating shaft, a crown (3) mounted coaxially and rotationally free on the hub (2), at least one elastic group (30) arranged circumferentially with respect to the hub (2) and the crown (3) and interposed, each, between a pair of first elements (50) integral with the hub (2) and between a pair of second elements (16) integral with the crown (3), the pulley (1) comprising a dust protection lip (50) carried integrally by said hub (2) and configured to slide, in tight manner, with respect to an element (7, 8) integral with said crown (3), said dust protection lip (50) being a labyrinthine sealing lip.