Double Check Valve Damping for Construction Equipment Noise
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Solution Overview
Problem
Existing double check valves in construction machines experience abrupt opening and closing operations due to external loads, leading to noise and hunting phenomena when operating on slopes.
Innovation Solution
A double check valve design featuring pistons with plunger ground portions and notch portions, allowing for delayed opening and closing by utilizing hydraulic fluid flow rates to form pressure in plunger ground portions, which slows the movement of pistons and reduces abrupt pressure changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the check valve opens and closes abruptly in response to external load, then the valve responds quickly to pressure changes, but noise and hunting phenomenon increase
Solution Approach 1:
The patent introduces a damping mechanism as an intermediary element between the check valve and the hydraulic system. This damping mechanism mediates the pressure changes, allowing the valve to respond to external loads while filtering out abrupt pressure fluctuations that cause noise and hunting phenomenon.
Solution Approach 2:
The patent modifies the pressure parameters by introducing a damping mechanism that changes the pressure transmission characteristics. This allows the system to maintain quick response to legitimate pressure changes while attenuating the harmful high-frequency pressure fluctuations that cause noise and hunting.
2Reliability
If the check valve opens and closes rapidly, then the valve maintains good sealing performance, but impact and hydraulic cylinder stoppages occur
Solution Approach 1:
The patent applies beforehand cushioning by introducing a damping mechanism that anticipates and cushions against abrupt pressure changes before they reach the check valve. This cushioning effect maintains sealing performance while preventing the harmful impacts and stoppages that would otherwise occur.
3Reliability
If the valve responds immediately to pressure changes, then the checking function is maintained, but workability and reliability decrease due to hunting phenomenon
Solution Approach 1:
The damping mechanism serves as an intermediary that preserves the checking function by maintaining pressure differential across the valve while filtering out the hunting phenomenon. This allows the valve to maintain its sealing function without the harmful rapid oscillations that reduce workability.
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 design significantly reduces noise and hunting phenomena, improving workability and reliability by delaying the opening and closing of check valves in response to external loads, thus minimizing impacts and hydraulic cylinder stoppages.
Implementation Method 1
the check valves b and c that are elastically supported by the first and second elastic members e1 and e2
Implementation Method 2
a flow rate of hydraulic fluid having passed through the notch portions forms pressure in the plunger ground portions of the pistons
Data Source
AI summary
An improved double check valve for a construction machine is provided, which can greatly reduce noise and hunting phenomenon by making check valves open and close within a predetermined time difference to correspond to pressure drops that occur due to an external load when a dozer blade working device is operated. The double check valve includes a hydraulic pump; a hydraulic cylinder connected to the hydraulic pump to drive a working device; a control valve installed in a flow path between the hydraulic pump and the hydraulic cylinder and shifted to control a start, a stop, and a direction change of the hydraulic cylinder; a pair of pistons installed on one side of a piston cylinder to open and close first flow paths and second flow paths provided between the control valve and the hydraulic cylinder, provided with plunger ground portions and notch portions, respectively, and dividedly formed to be shifted in opposite directions to each other when signal pressure that is introduced from any one of the first and second flow paths acts on check hydraulic pressure portions during temporary descending of the working device; a pair of check valves of which checking functions are released when the check valves are pressed through the shifting of the pistons; and a plunger installed inside the piston cylinder to move the pistons in a checking function release direction of the check valves while a flow rate of hydraulic fluid, having passed through the notch portions, forms pressure in the plunger ground portions of the pistons.