Hydraulic Damper Spool Valve Pressure-Flow Control
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Solution Overview
Problem
Existing variable orifice damper valves for hydraulic dampers are complex, sensitive to manufacturing tolerances, and lack predictability in pressure-flow characteristics, making them challenging to manufacture and maintain a consistent performance over time.
Innovation Solution
A hydraulic damper spool valve with proportionally blocked shaped apertures that open and close in response to pressure differentials, using a pair of valve spools and a coil spring to create a mathematically predictable and precise pressure-flow relationship, reducing complexity and improving repeatability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If compliant plates are used to create a variable orifice damper valve, then the pressure-flow characteristic can be adjusted, but the system becomes highly sensitive to manufacturing tolerances and assembly variations
Solution Approach 1:
The patent replaces the mechanical compliant plate system with a spool valve mechanism that uses hydraulic pressure to control aperture opening. This substitution eliminates the sensitivity to plate thickness, material properties, and assembly tolerances while maintaining the ability to adjust pressure-flow characteristics through the spool valve geometry and spring preload.
Solution Approach 2:
The patent changes the control parameter from mechanical plate deflection to hydraulic pressure acting on the spool valve. The spool valve aperture opening is directly controlled by the balance between spring force and hydraulic pressure, providing a more predictable and controllable parameter relationship that is less sensitive to manufacturing variations.
2Adaptability or versatility
If compliant plates are used to create a variable orifice, then the pressure-flow characteristic can be varied, but the characteristic cannot be easily predicted using mathematical techniques
Solution Approach 1:
The patent replaces the complex mechanical deformation of compliant plates with a hydraulic spool valve system where the aperture opening can be mathematically predicted based on spring force balance and hydraulic pressure relationships. This provides a clear analytical model for predicting pressure-flow characteristics.
3Adaptability or versatility
If compliant plates are used in a damper valve, then variable orifice control is achieved, but the pressure-flow characteristic diverges from its original curve over time due to material fatigue and particle accumulation
Solution Approach 1:
The patent replaces the compliant plate system with a spool valve that has no flexible elements subject to fatigue. The spool valve mechanism consists of rigid components that do not degrade over time, and the aperture opening is controlled by hydraulic pressure balance rather than material deflection, eliminating the divergence from original performance characteristics.
4Ease of manufacture
If a complex assembly approach is used to attach plates and piston to shaft, then some dimensional limitations are overcome, but the variation associated with dimensional accuracy of the plates themselves remains
Solution Approach 1:
The patent replaces the complex assembly of attaching compliant plates to the piston and shaft with a spool valve mechanism that is mounted to the piston. This eliminates the need for precise attachment of flexible elements while maintaining dimensional accuracy through the rigid spool valve construction.
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 highly predictable and precise bi-directional pressure-flow relationship, reducing manufacturing costs and improving performance by using only two moving components, and allowing for tuning of pressure-flow characteristics through coil spring adjustments and aperture profiles.
Implementation Method 1
a coil spring or other resilient means arranged between the valve spools so as to bias them in opposing directions
Implementation Method 2
shaped apertures that are adapted to be proportionally opened and closed in response to the pressure differential across the main piston
Data Source
AI summary
A hydraulic damper assembly includes a main body, a shaft assembly and a main piston operatively configured to define an upper portion and a lower portion within the main body. A hydraulic damper spool valve is adapted to provide a single path, variable hydraulic flow restriction between the upper portion and lower portion of the main body. The hydraulic damper spool valve is configured with an array of precisely shaped flow apertures that are proportionally opened and closed by a pair of valve spools in response to the pressure differential across the main piston. The damper's pressure-flow operating characteristic is simply and predictably dictated by the geometric configuration of the shaped flow apertures. The precisely defined open area of the shaped flow apertures provides a mathematically predictable hydraulic flow restriction that operates predominately in a turbulent regime resulting in insensitivity to hydraulic fluid viscosity and consequently temperature change.