Shock Absorber Volume Reducing Insert for Noise Mitigation
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Solution Overview
Problem
Shock absorbers in automotive suspension systems generate clatter noises due to pressure waves caused by high-frequency piston accelerations, leading to undesirable resonances and vibrations.
Innovation Solution
A shock absorber design featuring a pressure tube, piston assembly, and fluid transfer tube with an intermediate chamber, where a valve assembly controls fluid flow between the chambers, and an insert reduces the volume of the fluid transfer channel to minimize pressure wave formation, thereby reducing noise and vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the intermediate chamber volume is reduced, then pressure wave formation is minimized, but the damping fluid capacity is reduced
Solution Approach 1:
The intermediate chamber is segmented into a main intermediate chamber and a smaller fluid transfer channel portion. This segmentation allows the majority of the damping fluid to be stored in the main chamber while minimizing the volume where pressure waves form during high-frequency piston accelerations.
Solution Approach 2:
The fluid transfer channel is designed with specific local characteristics including a reduced cross-sectional area and controlled length. This local quality modification minimizes pressure wave formation in the critical fluid transfer region while preserving the overall damping fluid capacity in the main intermediate chamber.
2Object-generated harmful factors
If the fluid transfer channel cross-sectional area is reduced, then pressure wave formation is minimized, but the fluid flow capacity is reduced
Solution Approach 1:
The fluid transfer channel incorporates an adjustable valve mechanism that dynamically controls the cross-sectional area. This allows the system to optimize fluid flow during normal operation while minimizing pressure wave formation during high-frequency piston accelerations by reducing the effective cross-sectional area when needed.
Solution Approach 2:
The system changes the physical parameters of the fluid transfer channel, specifically the cross-sectional area, based on operating conditions. The adjustable valve allows dynamic modification of this parameter to balance pressure wave minimization with adequate fluid flow capacity.
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, vibration, and harshness by minimizing pressure wave formation within the intermediate chamber, enhancing the overall performance and comfort of the vehicle.
Implementation Method 1
When the shock absorber undergoes compression and extension movements, the valve assembly controls fluid flow between the intermediate chamber and the second working chamber
Implementation Method 2
The piston has passageways and valve disk stacks that limit the flow of damping fluid between the two working chambers of the shock absorber when the shock absorber undergoes compression and extension. As a result, the shock absorber is able to produce a damping force that counteracts suspension movements and vibration
Data Source
AI summary
A shock absorber including a pressure tube, a piston assembly slidably disposed within the pressure tube, and a fluid transfer tube that extends about the pressure tube is provided. The piston assembly divides an inner volume of the pressure tube into first and second working chambers. An intermediate chamber between the pressure tube and the fluid transfer tube is arranged in fluid communication with the first working chamber. A valve assembly is disposed in fluid communication with the intermediate chamber and the second working chamber. The valve assembly controls fluid flow between the intermediate chamber and the second working chamber. At least part of the intermediate chamber is formed by a fluid transfer channel that extends longitudinally within the fluid transfer tube to provide a fluid flow path extending between the first working chamber and the valve assembly.