Pilot-Driven Shock Absorber Damping for Compact Valve Mounting
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Solution Overview
Problem
The existing fluid pressure shock absorbers face challenges in improving the mountability of damping valves capable of changing damping characteristics due to increased size requirements when dealing with high-pressure and high-flow-rate working fluids.
Innovation Solution
A fluid pressure shock absorber design incorporating a solenoid valve to switch pilot pressure for a pilot-driven damping valve, allowing the damping characteristic to be changed without increasing the size of the damping valve, using working fluid as pilot pressure and reducing the required solenoid thrust.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a solenoid valve is used as a damping valve to change damping characteristics, then the damping characteristics can be adjusted, but the valve size increases when handling high-pressure and high-flow-rate working fluids
Solution Approach 1:
The patent introduces a pilot pressure system as an intermediary mechanism. A small solenoid valve controls pilot pressure to act on a pilot piston, which in turn controls a larger damping valve. This allows a small control valve to regulate a larger main valve, solving the size problem while maintaining adjustability capability.
Solution Approach 2:
The patent replaces direct mechanical control of a large damping valve with a hydraulic/pneumatic control system using pilot pressure. The solenoid valve electronically controls pilot pressure, which then mechanically actuates the damping valve, substituting direct mechanical linkage with a fluid-mediated control system.
2Reliability
If a larger damping valve is used to handle high-pressure and high-flow-rate working fluids, then the valve can manage the flow, but the mountability is deteriorated
Solution Approach 1:
The pilot pressure system acts as an intermediary that allows a small solenoid valve to control a larger damping valve. The small valve handles the control function while the large valve handles the high-pressure flow, with the pilot pressure mechanism bridging between them. This enables high-pressure handling capability while maintaining compact installation footprint.
3Extent of automation
If the solenoid valve directly controls the working fluid, then the damping valve can be actuated, but a large solenoid thrust is required
Solution Approach 1:
The patent introduces pilot pressure as an intermediary force mechanism. The small solenoid valve generates small pilot pressure that acts on a pilot piston with larger surface area, amplifying the force to control the main damping valve. This force amplification allows automatic control with minimal solenoid thrust requirement.
Solution Approach 2:
The patent changes the pressure parameter distribution in the system. Instead of requiring high pressure at the solenoid output, the system uses low-pressure pilot control that gets amplified through the pilot piston area ratio. This parameter transformation allows small solenoid force to control large valve forces.
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 enhances the mountability of damping valves by maintaining a compact size while effectively adjusting damping characteristics based on load weight, improving operational efficiency and stability.
Implementation Method 1
a solenoid valve configured to switch supply and shut off of a pilot pressure to the damping valve
Implementation Method 2
a piston connected to the rod and dividing an interior of the cylinder tube into a bottom-side chamber and a rod-side chamber
Implementation Method 3
a damping valve configured to impart resistance to a flow of working fluid between the bottom-side chamber and the rod-side chamber
Data Source
AI summary
A fluid pressure shock absorber mounted on a vehicle includes: a cylinder tube; a rod inserted into the cylinder tube so as to be movable back and forth; a piston connected to the rod and dividing an interior of the cylinder tube into a bottom-side chamber and a rod-side chamber; a damping valve configured to impart resistance to a flow of working fluid between the bottom-side chamber and the rod-side chamber, the damping valve being capable of changing damping characteristic in response to a pilot pressure; and a solenoid valve configured to switch supply and shut off of a pilot pressure to the damping valve, wherein the working fluid in the bottom-side chamber or the rod-side chamber is used as the pilot pressure.