Non-symmetrical Spring Disc for Shock Absorber Damping Control
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Solution Overview
Problem
Existing shock absorbers face challenges in tuning damping characteristics between low and high piston speeds due to the exponential relationship between pressure drop and flow rate, leading to abrupt changes in damping, which affects vehicle handling and noise quality.
Innovation Solution
A valve disc assembly with a non-symmetrical spring disc that gradually opens along a circumferential path, allowing for tailored stiffness and controlled fluid flow, enabling smoother transition between low and high piston speeds by varying the fluid flow resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional symmetrical valve discs are used, then the structure is simple and easy to manufacture, but the damping characteristic changes abruptly between low and high piston speeds
Solution Approach 1:
The patent applies asymmetry by designing a valve disc with a non-symmetrical stiffness distribution around its circumference. The stiffness varies continuously along the circumferential path, creating different opening characteristics at different angular positions. This non-uniform stiffness profile enables gradual damping transitions while maintaining structural simplicity.
Solution Approach 2:
The valve disc incorporates local quality variations by having different stiffness characteristics at different locations around the disc perimeter. The stiffness is tailored locally to achieve specific opening pressures and flow characteristics at different angular positions, allowing precise control over the damping transition profile.
2Productivity
If the valve disc opens abruptly to control fluid flow, then the damping force changes quickly, but this causes harshness and noise in vehicle operation
Solution Approach 1:
The patent applies dynamics by creating a valve disc with continuously variable stiffness around its circumference. As pressure increases, different sections of the disc open at different angles rather than all at once, creating a progressive and dynamic opening sequence. This dynamic opening behavior smooths the damping transition and eliminates abrupt changes that cause noise and harshness.
Solution Approach 2:
The non-symmetrical stiffness distribution acts as a preliminary action by pre-positioning different sections of the valve disc to open at different pressures and angles. This pre-planned sequential opening prevents abrupt flow changes by gradually increasing the opening area as pressure builds, thereby reducing noise and vibration before they can occur.
3Ease of manufacture
If the valve disc stiffness is uniform, then the manufacturing is easier, but the ability to tailor damping characteristics between low and high speeds is limited
Solution Approach 1:
The valve disc incorporates local quality variations by having different stiffness characteristics at different locations around the disc perimeter. The stiffness is tailored locally to achieve specific opening pressures and flow characteristics at different angular positions, allowing precise control over the damping transition profile.
Solution Approach 2:
The patent applies parameter changes by varying the stiffness parameter continuously around the circumference of the valve disc. This creates a gradient of opening characteristics that enables precise tuning of damping behavior across different piston speeds while maintaining a single integrated disc structure that is relatively easy to manufacture.
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
This solution allows for improved control of damping characteristics between low and high speeds, enhancing vehicle handling and reducing noise and vibration issues by preventing abrupt disc movements, thus providing a more refined and efficient shock absorption mechanism.
Implementation Method 1
The spring disc has a non-symmetrical shape which enables a stiffness of the valve disc assembly to be tailored so that the valve disc assembly begins to open at a first peripheral point, and continuously gradually opens about a non-symmetrical circumferential path
Implementation Method 2
Because of the exponential relationship between pressure drop and flow rate, it can be difficult to tune the damping characteristic of the shock absorber between low and high piston speeds
Data Source
AI summary
A shock absorber for a vehicle is disclosed which has a pressure tube defining a fluid chamber, a piston rod, and a piston disposed within the fluid chamber, and carried on the piston rod, which divides the fluid chamber into upper and lower working chambers, and which has a plurality of passages extending between the upper and lower working chambers. A valve disc assembly controls a flow of fluid, and includes a spring disc. The spring disc has a non-symmetrical circumferential shape which enables a stiffness of the valve disc assembly to be tailored so that it begins to open at a first peripheral point, and continuously gradually opens about a non-symmetrical circumferential path until reaching a second peripheral point adjacent the first peripheral point.