Progressive-Rigidity Filtering Pulley for Torsional Vibration Damping
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Solution Overview
Problem
Existing filtering pulleys for internal combustion engines face a challenge in balancing the need to filter torsional vibrations while maintaining sufficient rigidity to handle high loads, as the rigidity of elastic elements must be low to effectively filter oscillations but cannot be lowered due to the high loads absorbed by accessories.
Innovation Solution
A filtering pulley design featuring a hub connected to a crank shaft with a ring and dynamic damper, incorporating progressive rigidity springs and an anti-warping device, which provides high rigidity for high torques and low rigidity for low torques, and includes a dynamic damper and elastomeric material for effective vibration absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the rigidity of elastic elements is lowered to effectively filter torsional oscillations, then the filtering performance is improved, but the ability to handle high loads deteriorates
Solution Approach 1:
The patent applies progressive rigidity springs that dynamically adjust their stiffness characteristic based on the operating conditions. At low torques, the springs provide low rigidity to effectively filter torsional oscillations. At high torques, the springs automatically increase their rigidity to handle the high loads. This dynamic adaptation resolves the contradiction by making the rigidity property variable rather than fixed, allowing the system to optimize both filtering performance and load handling capacity under different operating conditions.
2Object-affected harmful factors
If progressive rigidity springs are used to provide high rigidity for high torques and low rigidity for low torques, then both filtering performance and load handling are improved, but the device complexity increases
Solution Approach 1:
The patent changes the physical parameter of spring rigidity from a constant value to a variable value that depends on the applied torque. By using progressive rigidity springs with a specially designed coil spacing configuration, the system achieves automatic parameter adaptation without requiring complex control systems or multiple interchangeable components. The coil spacing is designed such that as the spring compresses under increasing torque, the effective stiffness increases progressively, providing the desired dual functionality in a single integrated element.
Solution Approach 2:
The patent employs composite construction within the spring assembly, combining multiple spring elements with different coil spacing characteristics in a single integrated structure. This allows the system to exhibit complex nonlinear elastic behavior that cannot be achieved with a simple uniform spring. The composite spring structure integrates both the low-rigidity and high-rigidity characteristics in one component, reducing overall device complexity while maintaining the ability to handle both vibration filtering and high load conditions.
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 pulley effectively filters torsional vibrations while maintaining high rigidity under high loads, ensuring reliable operation and preventing spring warping, with adjustable characteristics through varying spring coil spacing and combinations of spring types.
Implementation Method 1
at least one elastic assembly (40) arranged in the chamber (15), wherein the travel of the elastic assembly (40) in the chamber (15) is defined by an angular clearance
Implementation Method 2
The elastic assemblies (40) can comprise a spring with progressive rigidity, that is to say a spring having a rigidity which progressively increases from a value which is as close to zero as possible when the spring is free, ideally to a value which is as close to infinity as possible when the spring is compressed
Implementation Method 3
a dynamic damper (19) comprising a disc (21), facing the closing element (11) and having a portion of hub (22) integral with the hub (2), and a seismic ring (23) constrained to a perimeter flange (24) of the disc (21) by a ring (25) of elastomeric material
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
The filtering pulley (1) comprising a hub (2) adapted to be fixed to a rotating shaft, a ring (3) assembled coaxial and rotationally free on the hub (2), at least one elastic assembly (40) arranged circumferentially with respect to the hub (2) and to the ring (3) and each interposed between a pair of first elements (50) integral with the hub (2) and between a pair of second elements (16, 17) integral with the ring (3), the at least one elastic assembly (40) comprises at least one elastic element (41) having a progressive rigidity increasing starting from a predetermined threshold value of the angle of relative rotation between the hub (2) and the ring (3).