Filtering Pulley Preload Structure for Torsional Vibration Damping
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Solution Overview
Problem
Existing filtering pulleys in internal combustion engines suffer from noise, energy loss, and increased wear due to the impact of actuator elements on elastic elements and their seats, which are exacerbated by torsional vibrations.
Innovation Solution
A filtering pulley design featuring a hub, annular crown, elastic groups with circumferential interference, and an actuator that preloads the elastic groups to reduce axial and circumferential movements, minimizing noise and wear by damping torsional vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a filtering pulley with actuator elements and elastic elements is used to filter torsional vibrations, then the torsional oscillations are filtered, but noise is generated due to impact between components
Solution Approach 1:
The patent applies beforehand cushioning by providing a circumferential cushioning element between the actuator element and the elastic elements. This cushioning element prevents direct impact contact during operation, thereby reducing noise while maintaining the torsional vibration filtering function. The cushioning element is positioned in advance to absorb and dampen impact forces before they can generate noise.
2Stability of the object's composition
If a filtering pulley with actuator elements and elastic elements is used to filter torsional vibrations, then the torsional oscillations are filtered, but energy losses increase
Solution Approach 1:
The circumferential cushioning element is designed to minimize energy loss while providing necessary cushioning. It absorbs impact energy through elastic deformation and returns it to the system, rather than dissipating it as heat or noise. This maintains the overall energy efficiency of the torsional vibration filtering mechanism.
3Stability of the object's composition
If a filtering pulley with actuator elements and elastic elements is used to filter torsional vibrations, then the torsional oscillations are filtered, but wear between parts increases
Solution Approach 1:
The cushioning element acts as a protective layer between the actuator element and the elastic elements, preventing direct metal-to-metal or component-to-component contact. This reduces friction and wear, thereby extending the service life and improving the reliability of the filtering pulley components.
4Object-generated harmful factors
If a circumferential cushioning element is added to reduce noise and wear, then noise and wear are reduced, but device complexity increases
Solution Approach 1:
The circumferential cushioning element is implemented as a flexible, thin-walled structure that can be easily integrated into the existing pulley design. This flexible shell approach minimizes the added complexity while effectively providing the required cushioning function. The thin-film nature of the cushioning element allows it to be positioned in the circumferential direction without significantly increasing the overall device 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 and wear while maintaining efficient torque transmission by preventing axial and circumferential movements between the hub and crown, enhancing the pulley's durability and performance.
Implementation Method 1
one or more elastic groups (30) arranged circumferentially free in the chamber (15) and transmitting the torque between the hub (2) and the crown (3)
Implementation Method 2
The actuator (35) is placed in contact with the elastic groups (30) with a circumferential interference value so as to preload the elastic groups (30) inside the chamber (15)
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 at least one elastic group (30) is placed with a circumferential interference (β) with respect to the first elements (36) integral with said hub (2).