Frequency Dependent Shock Absorber Spool Valve
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional hydraulic dampers lack effective frequency-dependent passive valving systems that provide soft damping characteristics during both compression and rebound strokes, limiting their ability to isolate vehicle bodies from high-frequency road inputs effectively.
Innovation Solution
The development of a frequency-dependent hydraulic damper with a spool valve assembly and bypass valve system that adjusts damping based on road frequency, allowing for soft damping in both compression and rebound strokes by varying fluid flow paths and preloads, transitioning smoothly from soft to firm damping conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional hydraulic dampers use standard valving systems, then they provide consistent damping force, but they cannot provide soft damping characteristics for high-frequency road inputs
Solution Approach 1:
The valve assembly incorporates a mass member that dynamically responds to input frequency, automatically adjusting the damping characteristics without external control. At high frequencies, the mass member remains stationary allowing soft damping; at low frequencies, it moves to engage the valve seat for firm damping, making the system adaptive to different road conditions
Solution Approach 2:
The system changes the effective damping parameter based on input frequency through the inertial response of the mass member. The mass member's position changes with frequency, thereby changing the valve opening state and the resulting damping force characteristic from soft to firm
2Ease of operation
If frequency dependent damping devices operate only during extension/rebound movement, then they simplify the valving system, but they cannot provide soft damping during compression stroke
Solution Approach 1:
The valve assembly is designed to perform the frequency-dependent damping function in both compression and extension/rebound strokes. The same mass member and valve seat configuration operate during both directions of piston movement, providing soft damping during compression stroke just as effectively as during extension, eliminating the need for separate valving systems for each stroke
3Object-affected harmful factors
If hydraulic dampers provide firm damping characteristics, then they stabilize vehicle body, but they transmit high-frequency road inputs to the vehicle body
Solution Approach 1:
The system automatically changes the damping parameter based on input frequency detection through the mass member's inertial response. High-frequency inputs result in the mass member staying stationary, maintaining the valve in an open state for soft damping that isolates the vehicle body. Low-frequency inputs cause the mass member to move and close the valve, providing firm damping for stability
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 provides enhanced isolation of vehicle bodies from high-frequency disturbances by ensuring soft damping in both compression and rebound strokes, improving ride comfort and handling by dynamically adjusting damping characteristics in response to road frequencies.
Implementation Method 1
A spring is disposed within the frequency dependent valve assembly and biases the spool valve in an initial position. A force applied to the spool valve opposite to the biasing force of the spring moves the spool valve from the initial position.
Implementation Method 2
a first valving system is incorporated for generating damping force during the extension or rebound stroke of the hydraulic damper and a second valving system is incorporated for generating damping force during the compression stroke of the hydraulic damper
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A shock absorber has a pressure tube with a piston assembly slidably disposed within the pressure tube and attached to a piston rod. The piston assembly divides the pressure tube into an upper working chamber and a lower working chamber. The piston assembly includes a frequency dependent valve assembly attached to the piston rod which defines a housing attached to the piston rod and a spool valve assembly. The spool valve assembly includes a spool valve and a bypass valve assembly that controls fluid flow through bypass passage that bypasses the piston assembly.