Damping Force Control Valve for Shock Absorber High Speed Stability
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Solution Overview
Problem
Conventional damping force control shock absorbers fail to maintain the soft mode damping force characteristic at high speeds due to increased pressure in the pilot chamber, causing leakage through the second variable orifice and resulting in unintended increased damping force.
Innovation Solution
A damping force control valve design that limits the fluid supply to the second and third channels, keeping the pressure at the inlets of the first and second variable orifices lower than the high pressure region, and utilizing a spool-controlled orifice configuration to manage fluid flow and pressure in the pilot chamber, ensuring the damping force remains low at high speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a conventional damping force control valve is used to control damping force in soft mode, then the damping force is reduced for ride comfort, but at high speeds the pressure in the pilot chamber increases causing leakage through the second variable orifice which increases damping force unintentionally
Solution Approach 1:
The patent introduces a first fixed orifice as an intermediary flow limitation device between the high pressure region and the second variable orifice. This intermediary component mediates the fluid flow, preventing excessive pressure buildup in the pilot chamber that would cause leakage through the second variable orifice, thereby maintaining reliable soft mode damping force characteristics at high speeds
Solution Approach 2:
The patent changes the flow parameters by introducing a first fixed orifice that limits the flow rate to the second and third channels. This parameter change ensures that the pressure at the inlets of the variable orifices remains lower than in the high pressure region, preventing unintended damping force increases while maintaining the soft mode characteristic
2Productivity
If fluid supply to the second and third channels is increased to maintain pressure, then the damping force control responsiveness is improved, but the pressure in the pilot chamber increases causing leakage and unintended damping force increase
Solution Approach 1:
The patent converts the potential harm of excessive fluid supply into a benefit by using the first fixed orifice to deliberately limit the flow. This controlled limitation prevents the harmful leakage effect while maintaining sufficient fluid supply for responsive damping force control, transforming the flow limitation from a restriction into a protective mechanism
Solution Approach 2:
The first fixed orifice acts as an intermediary flow control element that mediates between the high pressure region and the variable orifices. It allows sufficient flow for responsiveness while preventing excessive pressure that would cause leakage, thus resolving the contradiction between responsiveness and leakage prevention
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 solution effectively maintains the damping force characteristic in the soft mode at high speeds by limiting fluid leakage and pressure in the pilot chamber, preventing unintended increases in damping force, thus enhancing the shock absorber's performance.
Implementation Method 1
a first fixed orifice (Kr) formed in the second ring disk (86), and a second fixed orifice (Kc) formed in the first ring disk (82)
Implementation Method 2
a spring (83) arranged in the hollow spool rod (80)
Data Source
Figure 1
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AI summary
The present invention relates to a damping force control valve and a shock absorber using the same. An object of the present invention is to provide a damping force control valve, in which the damping force characteristic at a high speed is maintained in a low level, and a shock absorber using the same. According to the present invention for achieving the object, there is provided a damping force control valve, which includes a high pressure region in communication with a tension chamber of a cylinder and a low pressure region in communication with a reservoir chamber, and controls a damping force by adjusting pressure of a pilot chamber by orifices, each of which has a channel controlled to open or close by a spool. The valve comprises a main valve installed between the high and low pressure regions and controlled to open or close according to pressure of the high pressure region, an initial preload and pressure of the pilot chamber, the main valve allowing working fluid to flow from the high pressure region to the low pressure region when being opened; a first fixed orifice in communication with the high pressure region; a bypass channel for discharging the working fluid supplied by opening a first variable orifice to the low pressure region, the first variable orifice making the first fixed orifice and the low pressure region communicate with each other; and a second fixed orifice for controlling the working fluid discharged to the low pressure region so that the working fluid supplied by opening a second variable orifice controls a pressure of the pilot chamber, the second variable orifice making the first fixed orifice and the pilot chamber communicate with each other.