Common Back-Pressure Chamber for Hydraulic Shock Absorber Damping Control
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Solution Overview
Problem
Existing controllable damping force hydraulic shock absorbers face challenges in controlling damping force characteristics across various piston speed regions, particularly in intermediate and high speed regions, due to complexity and increased manufacturing costs associated with independent hydraulic passages for extension and compression strokes.
Innovation Solution
A controllable damping force hydraulic shock absorber with a simplified structure featuring a common passage between extension-side and compression-side back-pressure chambers, a damping force controlling valve, and a pressure control type poppet valve to manage valve-opening pressures for both strokes, allowing for efficient damping force control across a wide range of piston speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If independent hydraulic fluid passages are provided for extension and compression strokes with pilot type damping force controlling valves, then damping force characteristics can be controlled within a wide range, but the structure becomes complicated and manufacturing costs increase
Solution Approach 1:
The patent merges the extension-side and compression-side hydraulic passages by making them communicate with a common back-pressure chamber through a communication passage. This allows a single damping force controlling valve to control both extension and compression damping forces, reducing structural complexity while maintaining wide-range damping control capability
Solution Approach 2:
The common back-pressure chamber serves multiple functions: it receives hydraulic fluid from both extension and compression sides, and communicates with both main valves. The single damping force controlling valve also performs dual function by controlling both extension and compression damping forces through the communication passage, achieving multi-functionality with reduced components
2Adaptability or versatility
If a pilot type damping force controlling valve is provided for each stroke, then orifice and valve characteristics can be controlled simultaneously, but the number of components increases affecting durability and reliability
Solution Approach 1:
The patent combines the extension-side damping force controlling valve and compression-side damping force controlling valve into a single integrated damping force controlling valve. This valve controls both main valves through a communication passage connected to the common back-pressure chamber, reducing the number of components while maintaining the ability to control both orifice and valve characteristics
Solution Approach 2:
The single damping force controlling valve performs the function of both extension and compression damping control. By communicating with the common back-pressure chamber and both main valves, it achieves multi-functionality, controlling damping characteristics across all piston speed regions while improving reliability through fewer 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
This solution enables effective control of damping force characteristics across all piston speed regions, reduces manufacturing complexity and costs, and enhances durability and reliability by using a shared hydraulic fluid passage system for both extension and compression strokes.
Implementation Method 1
an extension-side orifice passage for introducing the hydraulic fluid from the extension-side hydraulic fluid passage to the extension-side back-pressure chamber; a compression-side orifice passage for introducing the hydraulic fluid from the compression-side hydraulic fluid passage to the compression-side back-pressure chamber
Implementation Method 2
a common passage for allowing communication between the extension-side back-pressure chamber and the compression-side back-pressure chamber
Implementation Method 3
a damping force controlling valve for controlling flow of the hydraulic fluid in the common passage
Implementation Method 4
an extension-side main valve provided in the extension-side hydraulic fluid passage; an extension-side back-pressure chamber for controlling a valve-opening pressure of the extension-side main valve
Data Source
AI summary
A controllable damping force hydraulic shock absorber including a pilot type damping valve having a back-pressure chamber for each of an extension stroke and a compression stroke. A piston connected to a piston rod is fitted into a sealed cylinder in which a hydraulic fluid is contained. During an extension stroke of the piston rod, the hydraulic fluid in an upper cylinder chamber flows to a lower cylinder chamber through an extension-side hydraulic fluid passage, an extension-side orifice hydraulic fluid passage, an extension-side back-pressure chamber, an axial hydraulic fluid passage, a radial hydraulic fluid passage, a compression-side back-pressure chamber, an extension-side check valve and a compression-side hydraulic fluid passage. During a compression stroke, the hydraulic fluid in the lower cylinder chamber flows to the upper cylinder chamber through the compression-side hydraulic fluid passage, the compression-side orifice passage, the compression-side back-pressure chamber, the radial hydraulic fluid passage, the axial hydraulic fluid passage, the extension-side back-pressure chamber, the compression-side check valve and the extension-side hydraulic passage. The hydraulic fluid passage for an extension stroke and the hydraulic fluid passage for a compression stroke have some elements in common, thus simplifying the structure of the controllable damping force hydraulic shock absorber.