Amplitude Sensitive Hydraulic Damper With Independent Spring Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing hydraulic dampers with amplitude-sensitive damping (ASD) arrangements struggle to independently control and predefine the activation forces for rebound and compression strokes, leading to symmetric damping force characteristics and inability to activate only after a predefined pressure threshold, which limits the adjustment of damping force vs. piston velocity and displacement.
Innovation Solution
Incorporating a slidable partition assembly with an internal piston supported by an internal spring and an external piston supported by an external spring, where the internal piston is free to rotate and has a projection to prevent excessive compression, and a switchable valve to control hydraulic connections between main and additional chambers, allowing for independent adjustment of damping characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single spring supports the slidable partition in prior art dampers, then the structure is simple, but the activation force cannot be independently controlled for rebound and compression strokes
Solution Approach 1:
The single spring support structure is segmented into two separate springs: a first spring supporting the slidable partition for rebound stroke control, and a second spring supporting it for compression stroke control. This segmentation enables independent adjustment of activation forces for each stroke direction, resolving the contradiction between adaptability and complexity.
2Adaptability or versatility
If springs are disposed on opposite walls of the additional pressure chamber, then both compression and rebound forces are supported, but the damping force characteristic becomes symmetric
Solution Approach 1:
The spring support arrangement is made asymmetric by positioning the first spring on a first wall and the second spring on a second wall of the additional pressure chamber, with different preload forces. This asymmetric configuration enables different activation forces for rebound and compression strokes, achieving asymmetric damping force characteristics while maintaining structural clarity.
3Adaptability or versatility
If no switchable valve is used, then the ASD arrangement is always active, but the ability to activate only after predefined pressure threshold is lost
Solution Approach 1:
The system uses parameter changes in spring preload forces to control activation thresholds. By adjusting the preload forces of the first and second springs, the activation pressure thresholds for rebound and compression strokes are independently controlled, enabling threshold-based activation without requiring complex switchable valve systems.
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
Enables predefinition of activation forces for ASD, allowing for independent adjustment of damping force vs. piston velocity and displacement characteristics for both compression and rebound strokes, enhancing ride comfort and damping performance.
Implementation Method 1
a first spring to generate a first preload force on the slidable partition
Implementation Method 2
a second spring to generate a second preload force on the slidable partition
Implementation Method 3
each pressure difference between the sides of the partition will cause the partition to displace from its equilibrium position
Data Source
Figure 1~2
Figure 3
Figure 4a~4c
AI summary
A hydraulic damper (2), in particular a damper of a motor vehicle suspension is disclosed. The hydraulic damper (2) comprises a tube filled with working liquid, inside of which a slidable piston assembly (4) attached to a piston rod (6) led outside the damper (2) through a sealed piston rod guide (7) is disposed, said piston assembly forming at least one valve assembly of the damper, wherein each valve assembly (4, 04) of the damper separates the damper into a main compression chamber (10) and a main rebound chamber (9, 09) and is provided with rebound (41,041) and compression (42, 042) valve assemblies to control the flow of working liquid passing through it during rebound and compression stroke of the damper (2). The damper further composes at least one chamber in which a slidable partition assembly (54) separating this chamber into an additional compression chamber (101) hydraulically connected with a main compression chamber (10) and an additional rebound chamber (91) hydraulically connected with a main rebound chamber (9, 09), which slidable partition assembly (54) comprises a piston (541 ) making a sliding fit with the inner surface of the chamber and at least one spring (543) supporting the piston (541). In order to be able to predefine the forces of activation of the slidable partition assembly (54) and moreover to be able to predefine them independently for a rebound and compression side, in order to adjust force vs. piston velocity as well as force vs. piston displacement characteristics of a damper independently for its compression and rebound stroke said slidable partition assembly (54) additionally comprises at least one internal piston (542) disposed slidably within the external piston (541) and supported by an internal spring (544) disposed between said internal piston (542) and said external piston (541).