Rotational Damper Flanges for Noise Reduction
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Solution Overview
Problem
Existing rotary motion dampers are complex and unreliable in providing consistent damping of rotational movements, particularly in applications like motor vehicle components that require delayed return to rest position to avoid harsh noises.
Innovation Solution
A simplified design featuring an outer sleeve and axle with disc-shaped flanges that act as a slipping clutch, allowing the two components to twist relative to each other, providing friction at low torque and slipping at higher torque, thus delaying the return movement and achieving damping through a direct adaptation of plastic parts via injection molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional rotary motion dampers are used, then damping of rotational movement is achieved, but the construction becomes complex and reliability decreases
Solution Approach 1:
The damper is divided into two separate functional components: an outer sleeve containing the damping mechanism and an axle containing the drive mechanism. This segmentation allows each component to be optimized independently while simplifying the overall construction and improving reliability through modular design.
Solution Approach 2:
The axle is inserted into and nested within the outer sleeve, with the axle's flanges fitting into ring channels in the outer sleeve. This nested configuration allows the damping mechanism to be integrated within the drive mechanism, reducing overall complexity while maintaining functional reliability.
2Reliability
If friction is increased to delay return movement, then damping effect is improved, but frictional stress peaks occur at corners
Solution Approach 1:
The flanges are designed with locally different geometries: the head side is rounded to distribute frictional stress evenly and avoid stress peaks at corners, while the opposite side maintains a flat surface for effective damping. This local quality differentiation resolves the contradiction between consistent damping and stress concentration.
Solution Approach 2:
The head side of the flanges is rounded instead of having sharp corners, which distributes the frictional stress more evenly across the contact surface. This curvature eliminates stress concentration at corners while maintaining the necessary friction for damping effect.
3Strength
If plastic parts are adapted by injection molding, then direct adaptation and sufficient friction are achieved, but manufacturing precision requirements increase
Solution Approach 1:
The injection molding process parameters are optimized to achieve the desired friction characteristics and dimensional accuracy. By controlling parameters such as injection pressure, temperature, and cooling rate, the plastic parts achieve sufficient friction capability while meeting the required manufacturing precision for proper adaptation between components.
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 delays the return movement of components, reducing noise by managing friction and maintaining consistent performance across temperature fluctuations, ensuring reliable damping in applications like motor vehicle handles.
Implementation Method 1
the flanges with their flat flange surfaces are independent of temperature fluctuations with the same areal extension on the mating surfaces of the ring channels and act as a slipping clutch when the outer sleeve and the axle rotate against each other
Implementation Method 2
The effect of the slipping clutch is particularly required because the head side of the flanges is rounded. In this case, there are lower frictional stress peaks at any corners of the flanges opposite the annular channels, so that the effect of friction is essentially concentrated on the flat flange surfaces and the mating surfaces of the annular channels.
Data Source
Figure 1~6
Figure 7~13
AI summary
The invention relates to a rotational movement damper (1) comprising an outer sleeve (2) and an axle which fits in the outer sleeve (2) and mounted to rotate in the outer sleeve. The axle comprises at least two discoidal flanges (7, 8, 17, 18) with flat flange surfaces (9,10) and the same diameter, fitting in annular channels (12, 13, 14, 15) in the outer sleeve (2) such that the flanges contact with the planar flange surfaces (9,10) thereof against the equally planar area on the counter surfaces of the annular channels (12, 13, 14, 15) unaffected by temperature variations and, on counter-rotation of the outer sleeve (2) and axle (3) act as a slipper clutch.