Hydraulic Damper Piston Bleeding Layout for Low-Speed Ride Tuning
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Solution Overview
Problem
Existing hydraulic damper systems face challenges in independently tuning damper force characteristics for primary and secondary rides, particularly at low and medium velocity ranges, leading to difficulties in balancing car handling, comfort, and safety due to standard valve components influencing both low and high velocity characteristics.
Innovation Solution
A hydraulic damper assembly with a piston featuring radially and circumferentially spaced channels, including an additional channel at an oblique angle, and a proportional bleeding system between the compression and rebound valves, allowing for adjustable bleeding flow passages to reduce harshness and improve tunability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If standard valve components are used in hydraulic damper systems, then the device structure remains simple and easy to manufacture, but the ability to independently tune damper force characteristics for primary and secondary rides is limited
Solution Approach 1:
The valve system is segmented into multiple independent valve assemblies (compression valve assembly with first and second valve components, rebound valve assembly with third and fourth valve components). Each valve component can be independently tuned to control damper force characteristics at different velocity ranges, allowing separate optimization for primary and secondary rides without increasing overall system complexity
Solution Approach 2:
Different valve components are positioned at specific locations within the piston assembly to control fluid flow through specific channels (first compression channel, second compression channel, rebound channel). Each local valve component provides specialized damping control for its designated flow path, enabling independent tuning of damper characteristics while maintaining a relatively simple overall valve structure
2Object-affected harmful factors
If low compression forces with degressive characteristics are used to improve passenger comfort, then ride comfort is improved, but wheel-knuckle displacements increase leading to suspension closure or jounce bumper engagement
Solution Approach 1:
The compression valve assembly includes a first valve component that provides degressive damping characteristics at low velocities for comfort, and a second valve component that activates at higher velocities to provide progressive damping. This dynamic transition between different damping characteristics allows the system to be comfortable during normal operation while remaining safe during severe road conditions
Solution Approach 2:
The valve components are designed with different opening pressures and flow characteristics. The first valve component has lower opening pressure for comfort at low speeds, while the second valve component has higher opening pressure that activates during severe conditions. This parameter variation across different operating conditions allows the system to achieve both comfort and safety requirements
3Adaptability or versatility
If existing passive valve systems are used, then the device structure remains simple, but independent tuning of damper force characteristic for primary and secondary rides is difficult
Solution Approach 1:
The piston assembly is segmented into multiple independent valve assemblies (compression valve assembly with first and second valve components, rebound valve assembly with third and fourth valve components). Each valve component can be independently tuned to control damper force characteristics at different velocity ranges, allowing separate optimization for primary and secondary rides without increasing overall system complexity
Solution Approach 2:
The piston assembly serves multiple functions: it houses compression channels for compression stroke control, rebound channels for rebound stroke control, and multiple valve components that can be independently tuned. This multi-functionality allows a single passive valve system to provide independent tuning for both primary and secondary rides
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 enhances ride comfort and balance by providing improved damping characteristics at low and medium velocity ranges, reducing harshness and allowing for independent tuning of damper forces, thereby improving vehicle handling and safety.
Implementation Method 1
A proportional bleeding system is located between the compression valve and the piston to establish a bleeding flow passage between the at least one rebound chamber and the additional channel for reducing operation harshness
Implementation Method 2
Each valve assembly usually comprises a stack of resilient disks, often with an additional compression spring, covering the flow passages of the piston and acting as one way valve, deflecting or moving under the pressure of the working liquid to allow the medium flow
Implementation Method 3
A rebound valve is located in the compression chamber and covering the at least one rebound channel for limiting working fluid flow through the piston during the rebound stroke to provide a damping force during the rebound stroke
Implementation Method 4
Hydraulic suspension dampers typically comprise a tube filled with working liquid, inside of which a slidable piston assembly is placed
Data Source
AI summary
A hydraulic damper assembly comprises a housing defining a fluid chamber. A piston is slidably disposed in the fluid chamber dividing the fluid chamber into a compression and a rebound chamber. A piston rod couples to the piston for movement between a compression and a rebound stroke. The piston has a compression surface and a rebound surface. The piston defines at least one compression channel, at least one rebound channel, and at least one additional channel. A compression valve covers the at least one compression channel. A rebound valve covers the at least one rebound channel. A proportional bleeding system located between the compression valve and the piston to establish a bleeding flow passage between the at least one rebound chamber and the at least one additional channel for reducing operation harshness of the hydraulic damper assembly. A piston for the hydraulic damper assembly is also disclosed herein.