Hydraulic Damper Spool Valve With Separate Compression-Rebound Flow
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Solution Overview
Problem
Existing hydraulic damper valve technologies, particularly those using compliant plates or poppet-style pressure regulators, face challenges such as sensitivity to manufacturing tolerances, complex assembly processes, and unpredictable pressure-flow characteristics, which lead to inconsistent performance and wear over time.
Innovation Solution
A spool valve configuration with separate compression and rebound flow paths and shaped apertures, biased by resilient energy storage members, allows for mathematically predictable and stable pressure-flow characteristics by varying the open area of apertures in response to pressure differentials, eliminating the need for one-way valves and reducing wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If compliant plates are used to create a variable orifice, then the pressure-flow characteristic can be adjusted, but the characteristic becomes highly sensitive to manufacturing tolerances and assembly variations
Solution Approach 1:
The valve is segmented into fixed components (valve body with shaped aperture) and movable components (spool with leading edge), where each segment has a defined function. The shaped aperture provides the variable orifice area while the spool provides precise positional control, separating the functions of flow area definition and flow control.
Solution Approach 2:
The patent replaces the compliant plate's elastic deformation mechanism with a spool valve mechanism controlled by pressure differentials and spring forces. This substitution eliminates the need for precise control of plate deflection and reduces sensitivity to manufacturing tolerances of flexible components.
2Adaptability or versatility
If compliant plates are used to create a variable orifice, then the pressure-flow characteristic can be adjusted, but the characteristic becomes unpredictable and difficult to model mathematically
Solution Approach 1:
The patent uses a geometrically defined shaped aperture in the valve body that replicates the desired flow area profile. This geometric copy provides a predictable, mathematically definable flow path that can be precisely modeled, replacing the unpredictable elastic deformation of compliant plates.
Solution Approach 2:
The patent changes the geometric parameters of the shaped aperture (area, shape, position) to achieve different pressure-flow characteristics. These parameter changes are precisely controlled through spool displacement, allowing mathematical prediction of flow characteristics based on known geometric relationships.
3Adaptability or versatility
If compliant plates are used to create a variable orifice, then the pressure-flow characteristic can be adjusted, but the characteristic diverges from the original curve over time due to material fatigue and wear
Solution Approach 1:
Instead of using a flexible component that deforms to create the variable orifice, the patent inverts the approach by using a rigid component (spool) that moves to expose a pre-defined shaped aperture. This inversion eliminates material fatigue issues while maintaining the variable orifice functionality.
Solution Approach 2:
The patent uses durable, wear-resistant materials for the spool and valve body components that can withstand repeated cycling without degradation. The simple geometric design allows for easy replacement if wear occurs, while the overall system achieves long service life through robust component design.
4Adaptability or versatility
If compliant plates are used to create a variable orifice, then the pressure-flow characteristic can be adjusted, but the assembly process becomes complex and sensitive to dimensional tolerances
Solution Approach 1:
The patent combines the valve body with the shaped aperture and the spool into an integrated assembly where components fit together with standard tolerances. The shaped aperture is formed as part of the valve body geometry, eliminating the need for separate flexible plate components and their associated attachment complexities.
5Device complexity
If fixed orifices are used, then the structure is simple, but the pressure-flow relationship follows a squared law that is not desirable for controlling dynamic systems
Solution Approach 1:
The patent transforms the static fixed orifice into a dynamic variable orifice by introducing a movable spool that changes the effective flow area in response to pressure differentials. This dynamic adjustment allows the system to achieve desirable linear or digressive pressure-flow characteristics while maintaining relatively simple structural 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
The solution provides a robust, reliable, and cost-effective hydraulic damper with predictable pressure-flow characteristics, reduced manufacturing complexity, and improved durability by eliminating the need for one-way valves and check shims, while allowing tuning of flow between compression and rebound strokes.
Implementation Method 1
a pair of resilient energy storage members one of which is disposed between each valve spool and the valve body dividing section or membrane so as to bias the valve spools in opposing directions to the forces generated by the operating pressures
Implementation Method 2
an open area of the at least one shaped aperture adjacent the moving valve spool varies in proportional relationship to the pressure, thereby varying the hydraulic flow restriction
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A hydraulic damper spool valve (15) includes a pair of resilient energy storage members (47, 49) one of which is disposed between each of a valve spool (39, 41) and a valve body dividing section (27) so as to bias the valve spools (39, 41) in opposing directions to the forces generated by the operating pressures in the hydraulic fluid of the hydraulic damper (1). The valve spools (39, 41) are configured to vary the hydraulic flow restriction between the upper portion (11) and the lower portion (13) of the hydraulic damper (1). A compression hydraulic flow path is structurally separate from a rebound hydraulic flow path to prevent backflow via the other hydraulic flow path during hydraulic flow in either direction, each said flow path communicating with only the at least one shaped aperture (35, 37) adjacent the opposing end of one of the valve sleeves (23, 25).