Hydraulic Damper Anti-Noise Piston Ring Pressure Relief
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Solution Overview
Problem
Hydraulic damper assemblies experience squeaking noise due to the formation of high pressure oil cushions between the ring and the additional piston, caused by clearance gaps resulting from the ring bending during operation, which affects sealing engagement and leads to micro-leaks.
Innovation Solution
Incorporation of an anti-noise member in the recess of the additional piston, which releases fluid pressure between the ring and the upper surface, preventing the formation of high pressure oil cushions and ensuring proper contact to eliminate clearance gaps and micro-leaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the ring is allowed to bend during operation to engage the narrowed portion, then the hydraulic damper provides additional damping force, but a high pressure oil cushion forms between the ring and additional piston causing squeaking noise
Solution Approach 1:
A noise reduction member is introduced as an intermediary element between the ring and the additional piston. This member includes a noise reduction protrusion that contacts the ring, while its opposing surface contacts the additional piston, thereby mediating the interaction and preventing direct contact between the ring and piston that would generate noise.
Solution Approach 2:
The noise reduction member is extracted as a separate, independent component from both the ring and the additional piston. By making it a distinct element, the design allows the ring to bend and engage the narrowed portion for damping force while the noise reduction member independently manages the contact surfaces to eliminate noise generation.
2Ease of operation
If clearance exists between the ring and additional piston, then the ring can bend freely during operation, but micro-leaks occur due to the clearance gap maintaining separation
Solution Approach 1:
The noise reduction member acts as a mediator that bridges the gap between the ring and additional piston. Through the noise reduction protrusion contacting the ring and the opposing surface contacting the piston, it maintains continuous contact and prevents micro-leaks while allowing the ring to bend freely during operation.
Solution Approach 2:
The noise reduction member provides localized contact surfaces at specific points - the noise reduction protrusion contacts the ring at one location while the opposing surface contacts the additional piston at another location. This localized quality approach maintains sealing engagement at these specific contact points while allowing freedom of movement elsewhere.
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 anti-noise member effectively reduces noise generation during both compression and rebound strokes by maintaining proper contact between the ring and the upper surface, preventing the formation of high pressure oil cushions and thus eliminating squeaking noises.
Implementation Method 1
the anti-noise member releases fluid pressure between the ring and the upper surface of the recess thereby reducing noise generation
Implementation Method 2
the ring bends when entering an insert of a hydraulic compression stop or engaging a narrowed portion of the housing
Implementation Method 3
An additional piston couples to the piston rod, axially spaced from the main piston, located in the fluid chamber, to provide an additional damping force during the compression stroke and the rebound stroke
Data Source
Figure 1
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Figure 3
AI summary
A hydraulic damper assembly (20; 220) comprises a main tube (34; 222) extending between a first and a second end (36, 38; 224, 226) and defining a fluid chamber (40, 42; 228, 230) extending therebetween. A main piston (60; 244) slidably disposed in the fluid chamber divides the fluid chamber into a compression chamber (40; 228) and a rebound chamber (42; 230). A piston rod (66; 250) attaches to the main piston. An additional piston (100; 316) couples to the piston rod axially spaced from the main piston. The additional piston has a top surface (102; 318) and a bottom surface (104; 320) and defines at least one pathway (106; 322) extending through the additional piston. The additional piston defines a recess (112; 328) bounded by an upper surface (114; 330) and a lower surface (116; 332). A ring (118; 334) slidably is disposed in the recess. The additional piston includes an anti-noise member (120; 336) located in the recess whereby the anti-noise member releases fluid pressure between the ring and the upper surface reducing noise generation during a compression stroke and a rebound stroke.