Adjustable Shock Absorber Pilot Valve for Ultra-Low-Speed Damping
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Solution Overview
Problem
Existing damping force adjustable shock absorbers struggle to adjust damping force effectively when the piston speed falls within the ultra low speed range, as it takes a long time to generate the necessary differential pressure to open the ultra low speed valve.
Innovation Solution
The proposed damping force adjustable shock absorber includes a valve mechanism with a main valve, a pilot chamber, an introduction orifice, a pilot passage, and a control valve, where a low speed valve mechanism is provided in the pilot chamber. This mechanism increases the flow passage area when the piston speed reaches a given lower speed, allowing for effective damping force adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an ultra low speed valve is directly used in a piston of the damping force adjustable shock absorber, then the valve can handle ultra low speed conditions, but it takes long time to generate the differential pressure required to open the valve
Solution Approach 1:
The patent introduces a pilot valve as an intermediary component that operates at higher speeds to generate the differential pressure needed to open the ultra low speed valve. The pilot valve acts as a mediator that prepares the pressure conditions required for the main ultra low speed valve to function, solving the time delay problem by having a faster-responding component create the necessary conditions for the slower-responding component.
Solution Approach 2:
The pilot valve performs preliminary action by generating the differential pressure in advance before the ultra low speed valve needs to open. This preliminary pressure generation eliminates the time delay associated with waiting for natural pressure differential buildup, allowing the ultra low speed valve to open immediately when required.
2Ease of operation
If a main valve is used to control the working fluid flow, then the damping force can be adjusted, but the valve cannot open at ultra low piston speeds due to insufficient differential pressure
Solution Approach 1:
The pilot valve serves as an intermediary that creates the differential pressure conditions necessary for the main valve to open reliably. Without this intermediary mechanism, the main valve would fail to open at ultra low speeds due to insufficient pressure differential, making the system unreliable in low-speed conditions.
Solution Approach 2:
The patent replaces reliance on natural pressure differential buildup (passive mechanical system) with an active pilot valve mechanism that actively generates the required pressure differential. This substitution ensures reliable valve opening across all speed ranges by using an active control mechanism rather than passive pressure accumulation.
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 enables the shock absorber to adjust the damping force effectively even at ultra low piston speeds, ensuring proper operation and performance by generating the necessary differential pressure efficiently.
Implementation Method 1
a pilot chamber configured to exert a pressure on the main valve in a valve-closing direction
Implementation Method 2
an introduction orifice configured to introduce the working fluid into the pilot chamber
Data Source
AI summary
When a damping force adjustable shock absorber operates in a soft mode, a piston is performing a compression stroke, and a piston speed falls within an ultra low speed range, communication between an upper cylinder chamber and a reservoir is interrupted by an ultra low speed valve provided in a pilot passage. The interruption of communication enables expansion of an oil liquid in the upper cylinder chamber when the piston is performing the compression stroke and the piston speed falls within the ultra low speed range. A differential pressure is generated between an upper cylinder chamber side and a lower cylinder chamber side of a compression-side ultra low speed valve. As a result, when the piston speed falls within the ultra low speed range, the compression-side ultra low speed valve is opened, and a damping force having a valve characteristic achieved by the ultra low speed valve can be generated.