Shock Absorber Damping Force Control via Segmented Check Valves
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Solution Overview
Problem
Damping force control type shock absorbers using a single mechanism for both extension and compression strokes face limitations in achieving desired damping force characteristics, as adjustments to one stroke affect the other, restricting the control range.
Innovation Solution
A damping force control type shock absorber with a twin-tube structure, featuring a piston that divides the cylinder into two chambers, a base valve, and check valves that allow hydraulic liquid flow in both directions, along with a damping force control mechanism on the side wall of the outer tube, utilizing orifices and disk valves to adjust damping force characteristics independently for extension and compression strokes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single damping force control mechanism is used to control hydraulic liquid flow for both extension and compression strokes, then the device complexity is reduced, but the damping force characteristic control range is limited
Solution Approach 1:
The invention segments the single damping force control mechanism into two independent control mechanisms: a first damping force control mechanism for controlling hydraulic liquid flow during extension stroke, and a second damping force control mechanism for controlling hydraulic liquid flow during compression stroke. This segmentation allows independent adjustment of damping force characteristics for each stroke direction, resolving the contradiction between device simplicity and control versatility.
2Device complexity
If damping force characteristics for extension and compression strokes are adjusted using a single mechanism, then the device structure is simplified, but the ability to obtain desired damping force characteristics is reduced
Solution Approach 1:
The invention divides the damping force control function into separate mechanisms for extension and compression strokes. The first damping force control mechanism adjusts damping force characteristics during extension stroke by controlling hydraulic liquid flow through the first check valve, while the second damping force control mechanism adjusts damping force characteristics during compression stroke by controlling hydraulic liquid flow through the second check valve. This segmentation enables precise independent adjustment of damping force characteristics for each stroke direction.
Solution Approach 2:
The invention employs dynamic check valves (first and second check valves) that can open and close based on flow direction and pressure conditions. These check valves work in conjunction with the respective damping force control mechanisms to dynamically direct hydraulic liquid flow through appropriate passages, enabling the system to achieve desired damping force characteristics for both extension and compression strokes with high adjustment precision.
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
Enables the achievement of desired damping force characteristics for both extension and compression strokes, improving ride quality by allowing independent adjustment of damping forces, reducing scuttle shake and thrusting-up load, and enhancing installability and steering stability.
Implementation Method 1
a first check valve provided in the piston to allow a flow of hydraulic liquid from the second chamber toward the first chamber, a second check valve provided in the base valve to allow a flow of hydraulic liquid from the reservoir toward the second chamber
Implementation Method 2
The hydraulic liquid flow is controlled to generate a damping force by a damping force generating mechanism comprising an orifice, a disk valve, etc.
Implementation Method 3
An orifice passage is provided in parallel to at least one of the first and second check valves. A sub-check valve is provided in the orifice passage. The sub-check valve opens at a lower pressure than the check valve to which the orifice passage is provided in parallel
Data Source
AI summary
During either of the extension and compression strokes, hydraulic liquid flows from a cylinder upper chamber into a reservoir through an annular passage and a damping force control mechanism, and a damping force is generated by the damping force control mechanism. The check valve is provided with a sub-check valve in parallel thereto, which opens in a very low piston speed region to allow the hydraulic liquid to flow through an orifice passage. These check valves are opened successively as the piston speed increases, thereby generating a sufficiently small damping force in the very low piston speed region during the compression stroke of the piston rod, and obtaining a moderate damping force when the piston speed increases.