Parallel-Valve Shock Absorber for Low-Speed Damping Durability
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Solution Overview
Problem
Shock absorbers with parallel valves that open in the same stroke face durability issues, particularly at low piston speeds, as existing designs do not adequately manage the differential pressures and flow rates effectively.
Innovation Solution
A shock absorber design featuring a piston with dual damping force mechanisms, including a first and second damping force generating mechanism, where the second mechanism is activated at low piston speeds to improve durability by managing differential pressures and flow rates through specific valve configurations and orifice placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two valves are disposed in parallel to handle different piston speed regions, then the damping force control across different speed ranges is improved, but the durability of the low-speed valve deteriorates due to inadequate pressure management
Solution Approach 1:
A cap member is introduced as an intermediary component between the piston and the valve seat member. This cap member creates a cap chamber that manages pressure distribution, preventing excessive differential pressure from acting directly on the low-speed valve. The cap member mediates the force transmission while protecting the valve structure.
Solution Approach 2:
The valve seat member is provided inside the cap member, creating a nested structure. The first sub-valve is disposed in the other side chamber while the second sub-valve is disposed in the cap chamber. This nested arrangement allows independent pressure management in different chambers, protecting the valves from excessive differential pressure while maintaining damping control functionality.
2Adaptability or versatility
If valves are disposed in parallel to open one valve at low speed and both valves at higher speed, then the damping characteristics are improved, but the structural complexity increases
Solution Approach 1:
The first sub-valve and second sub-valve are integrated into a single valve seat member, which is then nested within the cap member. This merging of valve structures reduces the number of separate components compared to having completely independent valve assemblies, while still achieving the desired parallel valve operation for different speed regions.
Solution Approach 2:
The valve seat member serves multiple functions: it houses both the first sub-valve and second sub-valve, provides seating surfaces for both valves, and is positioned within the cap member to benefit from the pressure management system. This multi-functionality reduces the need for separate components for each valve function.
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 design enhances the durability of the shock absorber by optimizing valve operation at varying piston speeds, ensuring efficient fluid flow and pressure management, thereby improving the overall performance and longevity of the system.
Implementation Method 1
a first passage and a second passage through which the working fluid flows from a chamber on an upstream side to a chamber on a downstream side in the cylinder by a movement of the piston
Implementation Method 2
a first damping force generating mechanism which is provided in the first passage provided in the piston and generates a damping force; and a second damping force generating mechanism which is provided in an annular valve seat member disposed in the other side chamber, is provided in the second passage which is parallel to the first passage, and generates a damping force
Implementation Method 3
In the second passage, an orifice is disposed on an upstream side or a downstream side from the first sub valve in flow by which the first sub valve is opened
Data Source
AI summary
A valve seat member is provided in a cap member. A first sub valve is provided in another side chamber. A second sub valve is provided in a cap chamber formed between a bottom portion of the cap member and the valve seat member. In a second passage, an orifice is disposed on an upstream side or a downstream side from the first sub valve in flow by which the first sub valve is opened. In a region in which a piston speed is low, a valve of a second damping force generating mechanism is opened in a state in which a valve of a first damping force generating mechanism is closed. In a speed region in which the piston speed is higher than in another region, the valve of the first damping force generating mechanism and the valve of the second damping force generating mechanism are both opened.